I use a .8 - 1.0 coil at about 12 -14 watts. Power on my mods measure in % on a potentiometer, so translation = thereabouts.Hi - was all set to wade in and suggest, but others will nail it where I can't. I use the Samsung 30Q and Sony VTC6 at low power and get decent runtime. They're both about 3000 mAh, though I don't know if they'll stretch to 20A. If you vape at less than (say) 30W, they should be ok. There's always the Sony VTC5A (2600mAh / 25A) if you need more.
As for shiny-new, there's the recent Samsung 24S - see Mooch's review here.
Sorry I couldn't be of more help!
I've just really loved the time I got on the LG HG2's. They go for days!
Sent from my SM-N950U using Tapatalk