Mcbain

I have used the pass through 's you looking to get and would not recommend them at all. The wires are very small and very weak. I do have some, but will not sell them. They are not worth the money. The last one I used worked about 4 days and it was toast. Please look for what Tam suggests you will be much better off. Take it from someone that has them and knows.

It looks like it may be a 401. If this true you can screw the two batteries together, 401s are reverse 510 thread. Or you can screw the two carts together to test it as well. If you can do this you would a 401 to 510 adapter,

I personally recommend at least 2 of any of the following:
LG ICR18650HE2
LG ICR18650HE4
Samsung INR18650-25R R2 (BLUE)
Samsung INR18650-25R R5 (GREEN)
And at least one of the following:
Nitecore D2 Digicharger
Nitecore D4 Digicharger
Nitecore i2 Intellicharger
Nitecore i4 Intellicharger
I personally don't recommend any Efest batteries, especially for newbies.  Efest has been inconsistent at best.  They over rate the batteries that they rewrap and over charge for them.  I have seen independent tests that say none of their batteries are close to the rating they claim.  Is it true?  I don't know.  They have been the worst batteries I have ever had myself.
I also don't recommend Sony VTC3, or VTC4, as there are too may knock offs out there.  If you really trust the vendor, they are great batteries.  They are highly counterfeited though.
I think one of the more important things is choose the correct vendor.  Stay away from most vape sites, and Ebay.  Be very cautious on Amazon, as there are good ones and bad ones out there.  The safest places to buy them is Flashlight suppliers such as illumn.com, or liionwholesale.com (IMO).
Any of these batteries should be able to be bought for around $5.00 to $6.00 each.  I would suggest you buy at least 2.  This gives you a fresh backup at all times. This is another reason to get a separate charger.  You can be vaping on one, and charging the other.  I personally carry 4 everywhere I go, and keep 4+ fresh ones at home.  Normally 1 will last me nearly all day.  I am not a big fan of charging in the mod.  I also discourage "pass through" vaping especially with a SubOhm tank.

Well said Jason!
I agree with everything 100%

You just got some very good advice from Jason. 

I don't personally vape tobacco flavors, so I can't make recommendations on any tobacco flavors.  I can, however, make recommendations on how you can go about finding the flavor that is right for you.  
Everything in the vaping world is subjective - especially when it comes to e-liquid.  I find it much easier to find a person who likes the same setup (mod, tank and coil) as me than I do a person who likes the same flavors as me.  Everybody's taste buds are different and everybody is going to like different flavors.  To borrow an analogy from another member here on VT, what may taste out of this world to me could very well taste like wet socks to you.
One to my recommendation: make a visit to a B&M (or multiple B&M's).  I have visited a lot of B&M's specifically for the purpose of trying new flavors.  A good B&M (and no, they aren't all good) will have employees who are intimately familiar with each line of liquid they carry.  They may not know how it tastes, but they should know how well it sells and that should be an indication of whether or not a particular flavor is worth trying.  They should also know specifically which tobacco flavors they sell so they can help you with trying tobacco flavors specifically rather than you spending you time looking at their "menu".  Visiting a B&M to try different liquids doesn't obligate you to purchase from them.  That is entirely up to you.  Unless the liquids they are selling are "house blends" (made specifically by them), chances are you will find it cheaper somewhere online.
Last recommendation - Keep an open mind when trying e-liquids.  You may surprise yourself and find something non-tobacco flavored you like.  

Post a new topic in the eliquid section of the forum exlaining you are looking for suggestions for a tobacco flavor. 
I have not vaped a tobacco flavored ejuice since I discovered a cappuccino flavor about 2 weeks in to vaping 2 1/2 years ago, lol. Now, I hate tobacco flavors so I'd be of no help. I vaped Liqua American blend for 2 weeks and it got me off cigs.

Sorry. It used to be easier, lol
You're going to have to do a little research on your own as it's just too much to cover in one post. 
Here are a coupke things you should know to get you started:
There are some industry standards in place to allow the connection of various devices with each other. 
There are 3 particular areas of interest:
- the tank or tank/atomizer (coil),
-the battery or power source
-and the juice itself.
They can each be researched separately but in the case of the hardware (tanks and batteries) they are sometimes paired with each other even though they are cross compatible with other devices. 
There are some proprietery combinations that are not cross compatible (like cigavette). 
Harware manufacturers areare, generally, not concerned with liquid and vice versa.
The iStick is a brand of power source. It does not include the tank or juice
You should research these areas, browse websites like Vaportalk and ask specific questions here for advice.    Good luck!

Bu todays standard 1300mah ego is not that big. Plus, the Mega is fixed voltage output - you can't vary it to increase power. 
The Mega is 2 year old technology and it is not a cross compatible design. It was IMO a money grab aimed at a market at the time meant to lock people in to their device.  A lot has changed since then.
These days, the simple tank options like the Nautilus with a variable voltage battery like the Spinner or a high mah box mod like the iStick 30 or 50 are out performing all that stuff.  

I was a 2.5 - 3 pack a day Red smoker.  A inexpensive eGo style spinner battery with a Kanger Pro Tank mini 2 or 3 with 36mg/ml would make me cough and the nicotine would make me dizzy. 
I can buy 2 complete setups and enough juice to last a week for the price of the "Mega Set"  Once you buy it, you own it.  You can change tanks, buy juice from any vendor, in any flavor, for a fraction of the cost.
Refilling is simple, and the cost savings alone would be worth it.
Most of us here have gone this route (changeable cartridges) and most failed miserably to satisfy enough to quit.  After you have quit and no longer are dependent on all of the chemicals in cigarettes, and need a small stealthy portable rig, you might pick one up.  It will help get you by in public, mowing the lawn, or working on the car, until you can get a real vape off of a "normal" setup.
Here is an example of the cost savings:
1 - iStick 50W $29.99/ea  (4400mah) battery
1 - Kanger Protank 2 9.99/ea
1 - Kanger replacement coils 5pack $4.95
You would come up with a total of $44.93 you still have $65 left over for a heck of a lot of juice or another setup for backups....  I vape quite a bit, and $65 worth of juice will last me close to a month!
 

I've helped dozens of smokers find a decent rig, and always push them towards simple box-mods like the iStick 50W or 30W, or eGo-style like the Vision Spinner (original), eGo-Twist, or Evod-twist, and the recommendation of Kanger ProTanks or Nautilus are dependable and rugged.  I prefer the Kanger tanks because they are cheaper, and the coils are also much cheaper. 
Jason is spot-on with his pricing and recommendation... but I would suggest picking up at least two tanks, and eventually pick up a second battery (as a back-up).  You should always have back-ups!!  Eventually, you can pick up additional tanks, coils, etc. as you are no longer wasting money on smoking.  Additional tanks allow you to have tanks ready for other flavors, so you can change your flavor without dumping/cleaning at tank.