I've been using the 901 exclusively on the passthrough and it work like a champ so far. One thing I've found that helps me, is I have 2 atties that I think are BE(bestecig) have a V shaped bridge and solid silver looking ring around it,and it would taste burn for awhile, I flood the hell out of it, and the taste will be great, itll turn bad after maybe 10 or more draws, and I'll drip 2 more drops in and it will taste great for awhile and I'll drip again when it starts to taste bad again. Before I would put a few drops in and it would always taste bad, and it had juice on it,but found flooding it helps tremendously, for me at least. If any juice comes out of the hole, I just wipe it with a paper towel. I don't even blow out the attie when i flood it. But yah works like a champ( don't know how the carts work with it as I drip)