These things are finicky, but once you get it, it's no so bad. Are you using heavy VG liquid? I've found the lemo to be pretty forgiving except for max vg, where the wicking has to be perfect or it just dry hits.
With cotton and max VG, I use the approach mentioned earlier - have piece of 24g kanthal doubled up and stuffed in the channel when finishing the wick.
With rayon, I get the wick wet & "glue" it next to the channel, then spin the chimney on. If done right, the wick won't move when attaching the chimney.
In the pics posted earlier, looked like too much cotton, then not enough.
If its leaking, check all seals. If they are intact and in place, then it won't leak unless you lay it on its side and one of the channels becomes open to air.