Hi,I have been using the subtank mini RBA v1 & v2 and over the last 8 months of using them I can say I have mastered wicking both,v1 RBA deck is modified and works good but for a vertical twisted kanthal (going to try Clapton soon) the v2 RBA coil with the two holes on the side is absolutely brilliant,I have modified the coils air holes at the very bottom which contacts with the pin,there is 4 holes and I just filed two away ,I'll put pics up if you ask. It works brilliant with a 4m diameter twisted kanthal at 0.4 and I can chain vape the tank dry. It's all about wicking right. Say if you made one and it is getting dry ,pick a bit of cotton out through the hole's,that solves it sometimes. I have a rather mad why of wicking the vertical coils. If your juice is high vg say 60 n up you need less cotton. And also the cotton pads wether they be muji,ko gen do or whatever,I use puff personally,aspire use it in triton coils,anyway,the outside off the pads are compacted so they need to get binned ,use the inside,sometimes one side can be used in some cases.Clean hands is a must. that youtube vid above,if you turned that Clapton so its vertical it would vape like a champ.if you modified the air hols at very bottom it turns it into another tank,huge vapour production and flavour,they can be such a good coil,I take my vertical tiwsted at 0.4 up to 50w and is brilliant,just as long as cotton is packed all around it.