@fiddleshe, have you tried Tidi Rayon balls. On the Rayon thread they're gaining popularity due to the quality is much better than Grahame Cellucotton Rayon.
Unfortunately I am unable to get any to try, due to being based in the UK. But all you folks in the US can get hold of it relatively easily and at reasonable prices.
Also Ulton Tripod (Atmizoo Tripod clone) may be of interest, as it can give you really good flavour due to bottom airflow, is relatively easy to build and can be setup for MTL or DTL (yes, it's unique RTA). 2fdeal has them in stock with the 3.4ml extension kit.
ULTON Tripod Style 316SS 22mm RTA Rebuildable Tank Atomizer 2ml/3.4ml Combo (1:1) - Silver
I've only tried one setup for DTL, but got to get the wicking right. But with MTL I think that it will be much easier.
And the Coppervape Hussar Project X RTA's are well worth a mention. The way you build them is very different, but it's really easy. They're certainly one RTA that end up in rotation somewhere.
@bombastinator, don't forget that it can also be caused by too high a mass coils (including specific heat capacity) and limited airflow. Found that out myself a few times from just trying different builds on different RBA's, but it's how you learn. Just need to remember to take notes.