I'll chime in on this one. I have a Russian 91% and sure the flavor is amazing on it, and its a nice platform to build on. I personally have a hard time with leaks or dry hits. Before anyone shouts suggestions at me, I've heard them all and done the research. For some reason, I find the device more finicky than I prefer.
My Pyrex RSST however...
Ever since I got it, its been my every day vape. I leave the fill plug on and it produces about as much vapor as a nice dripper. Like RipTrippers status.
What I do on my builds is I use 500 mesh, and have it hollow all the way down. The last one was too hollow actually so I had to put another sleeve of 400 mesh to add more wick material. I microcoil it with 28 ga kanthal at 2.4 ohms and I run it at 5.3-5.8 volts on my Provari (whoa!)
Its a beast. I've never had a machine quite like this one. As I vape, the juice flows up the wicks and the air goes down the tube, into the tank. In my case, it actually vapes worse when the fill cap is off (low vapor production). I know this seems to defy the laws of physics because you would expect it to work better without the fill cap, but it works great with the cap on.
The icing on the cake is that it's never leaked. I have it sideways in my pocket all the time. I'm just careful not to have the intake hole facing down, but other than that, it's never made a mess on me.
FYI, the pyrex RSST top cap fits far more snug than the original RSST cap. The caps are the same. I have a cap with 1/16" air hole and one with 5/64". I primarily use the 5/64. For me, the genny will never die. Cheap to build, great, clean flavor and vapes like a freight train. Maybe I just got a lucky build. If so, good for me!