I've been vaping mostly Orb 100% VG but it's really watery and thin. Last few bottles I've bought don't have their ingredients/percentages listed. They makers are Suicide Bunny, Stormy's, Blast & maybe a couple more.
As far as flooding, It's been at least two months since I've used the tank portion of my C2 and probably a month and a half since I've used any part of it. Flooding seemed to be an issue either/or. With the complete C2 I had many leaks that stained the bejesus out of shirt/pants pockets. I've also tried some cartos in IBTanked tanks running on a Super-T Simplicity and while I had no flooding or leaking, the vapor was unsatisfactory after 3mls Max. Then I have to throw away a nice little stainless steel tube (which, IMO, should not be disposable) and around a ml of juice.
With the Sophia the flavor and vapor are leaps and bounds better in any case. When it performs questionably (at least 6ml of juice) all I have to do is pull out the little cotton wick, dry burn the gunk off the coil, roll a wick, thread it, cut it, saturate the wick, put the tank on (which I can keep full during the whole process) and have a fresh, perfect vape. It takes less time than priming a carto and the waste is only a tiny piece of a cotton ball and eventually a coil (cost ~ 25 cents max).
I should also mention that I'm definitely the kind of guy that it really suits to tinker, modify, and fine tune stuff and rebuild coils and what not. I actually bought the Z2 C2 because I thought I wanted to avoid all of that. Turns out I enjoy it!