Have been using the Smok TFV4 sub-tank for the last few days, stock .2 tri coils & the RBA .It is a big tanl 24.5 mm dia but looks good on my Snow Wolf or IPV4S.
Stock .2 tri coils are massive 16mm dia x 30mm long

, these are rated from 40w to 130w

Do they actually perform to the rating ? Yeppers they really do but need max airflow @ 130w to keep vape temp acceptable.Prefer around 70w with the airflow about 1/2 shut for really flavoursome thick clouds.
The RBA base is a single coil design(dual coil is coming out) & have tried probably 10 different builds(have 2 x RBA base),squeezed in a dual coil , tried nickel coils, tried nickel kanthal mix.Juice channels are massive , which is great but need to wick it so it does not flood.
Top fill is really easy
Vaping a 10 wrap 26 gauge(.09 ohms) nickel build as i type this & quite a nice vape , set @ 70w 420f on the Snow Wolf & to 50w 420f 50 joules on the IPV4S .
Still undecided if i like this temp control , flavour seems washed out compared to Kanthal but that could easily be my old knackered taste buds.