I went from CE5's (clearomizer) to an AGA-T geni, back to a fogger V4 and now subtank.. those were my mains. The CE5's and the AGA-T both had the juice on the bottom. I never could get the mesh part down, and I am... to this day.. trying to get mesh to work and taste good.
The main problem with Genesis tanks, is it has to wick upwards or you have to do a "tilt". With a a genesis, you have to have the wick draw the juice up the wick.. once it's saturated, it can then fire and produce good flavor. If the wick doesn't wick the juice fast enough, you end up with dry hits (as in my case). There is a fine line between wick looseness, coil power, and juice thickness.
When the AGA-T was my main, I tried the mesh.. I oxidized the mesh several times, didn't work.. took it out, took a blow torch, burned the juice off.. still shorted. I pulsed it...nothing worked. I always had a hot leg by the positive side, and the rest of the coil never did get red. I had to go to silica. I made a silica U-wick and did a loose knot at the top and a horizontal coil... it worked and worked well for that time. I took it to a vape shop a few months ago with that setup, and I asked the pro what he thought before he saw or knew of the coil... He was impressed, at the flavor, but still tasted the silica. I bought some mesh last month and will give it another go one day.. but I doubt it'll work.. I've switched to an almost pure VG mixture.
Cotton is good for holding juice, but it doesn't move the liquid very fast or far. That's one reason it hasn't been used in many other clearomizers. Recently, the new tanks use cotton, which is no longer than 1/2 an inch.. so the juice doesn't have to travel far to get to the coil. In my fogger V4 RTA, It also has a short wick. I think the fibers of cotton are too loose. I have some cotton yarn, and even that doesn't wick as good as silica or mesh. However, in my drippers, I find nothing better to hold juice than loose cotton. It also expands to touch the inside of the whole coil. With mesh or silica, it's a bit too rigid, and there's a slight bit of a gap.
Lastly, genies tend to leak. Let's say you have a wick thrust down there, and it draws some liquid up.. what replaces the juice? it either has to create a slight vacuum, or there is another hole somewhere to let the hole in. If there's a vacuum, it will hinder the wicking process. If there's a hole, then juice will leak form the hole if it is on it's side. either way, it's not a perfect setup. In my AGA-T, I would leave the fill screw out.. and just never tip it on it's side... made me find new places to put my mod when I was out and about.
hope this helps some.