Personally I'm not a fan of dual
coils at lower voltages and especially a 3.3-3.4V eGo. Their alittle better on 3.7V PVs, but are still just okay. I find dual coils only really shine when used in the 4-5V range. I would also get some Boge 2.0ohm cartos and try those. They work great on the eGo. A good single coil can work just as well and won't drain your battery like a DC does.
As far as using 1.5ohm cartos on an eGo, I wouldnt do it, but that's up to you. The eGo is a mosfet driven PV and using 1.5ohm-1.7ohm cartos puts a lot of stress on the eGo mosfet and can fry it. Personally I wouldn't use anything below 2.0ohm on an eGo, but again that's up to you