I had an experience with my protank in wich the base didn't actually sit flush with the tank and it created air flow issues I didn't know how to identify at the time, buying a new base solved that issue. The most important issue facing any system requiring saturation or wicking is the pg/vg ratio. I have found60/40 pg/vg to perform well in cartos and clearos. anymore vg than that and you will have issues. I know the thread starter stated that their juice was atleast 65% pg so that being ruled out I would next look to wicking issues, loosening is a odd work around and never seems to solve air flow issues permanently without inevitable leaks. Your RBAs could be wrapped to tightly in the same fashion that Boyz-mom mouth piece needed to come away from the wick to enable juice flow, try looser wrapped wicks and watch a bunch more RBA guide videos. after that your main suspects would be voltage or airflow. If your pro-tank heads are low or standard resistance as most I have seen they wont need anything more than 5v (if I am wrong correct me.) so ensure your running in an appropriate range. And before you walk away all together, go with Wv2wins suggestion of a carto tank. I still use carto tanks primarily outside the house and always suggest them to frustrated vapers, very reliable and easy. I also personally think that carto vapor has a dryer more smoke like hit to it.
http://www.myvaporstore.com/Smoktech_DCTank_s/87.htm
I have used these for the last 4 months and have just recently purchased a few of the other smoktec tanks and am really happy with them as a workhorse when I don't feel like building or am in a rush. I always use single coil cartomizers instead of the Dual's for my ego batteries or anything regulated under 3.7 volts because I read about it being danergous otherwise lol, not to put you off. RBA not for everyone and without a lot of guidance its all hard knocks. I would avoid RBA till you get comfy with another system. A clearo is going to leak at some point, and when that time comes you have to dump it clean it and let it dry before reassembly to really solve the issue. also pinching and wicking and all that. Hassle that doesn't exist with carto tanks. Dripping is something I do only for juice flavors that only come in VG 100%. which isn't much, and I use RBA for that about 80% of that time. to start drippig you just need and old fashioned bridgeless atty a drip shield and tip. disposable again for peace of mind. Hope to have been of some help, its paramount to get past the learning curves headache to enjoy moving away from tobacco, if that's your motive.
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on my e-go twist I keep it on 3.4-3.6 and haven't gotten the burnt flavor yet.
