Based on the 2 mods you mentioned:
Innokin Coolfire 4 (40 watt)
-Any of the Innokin iSub series
tanks
-Innokin Axiom
Artery Nugget (50 watt)
-Innokin Axiom
-Aspire Cleito (not the Cleito 120)
These are what I would recommend, but there are a plethora of
tanks out there. Just dont get high wattage tanks like the Smok beast series as 40~50 watts ain't gonna cut it.