Thanks for all the responses to this. I think I may have either gotten a batch of 1.8 ohm coils that were improperly marked or it may be a QC issue, since I've been using the 1.5 ohm with the 3.7V output of a mech mod since I got started. I'll try switching to the 1.8s and see if there's a marked difference.
I want to like the new Kanger dual coils - the ones that fit the Protank 3s - but the vapor production seems anemic on those. Maybe I've just got to play with a VV a bit more.
Much as I love the idea of RBAs, I just never have the time to sit and perfect the builds, so these pre-builts are a great, easy-to-maintain alternative.
Any of you guys have experience getting the new dual coils to prime output? I'm not a cloud chaser or anything, but I still want a solid lungfull.