Hi Chilli!
The nose art must be indexed, 8 bit, 256 color. The alpha mask color (transparency) is 176|176|176.
I cannot tell you much on the noseart uploading/approval process, as Ive never done that before. But id guess that the time it takes till approval depends on the workload Skuzzy has.
The current skin viewer is not up to par with the game update. That means, you can use it, but youll have to rebuild game plane cache after each time you opened it.
Do you have any noseart show up in the game at the moment? (check while in F3 mode on the ground). If you do, you can "replace" that nosearts file with your own (need to name it the same) - but back the original up
. If you are squad CO, you should be able to use your own. It will always (no matter if the file has been approved) show up in game for you (but noone else! until its approoved).
(I did that a while ago when I was adjusting some nose arts. Just backed the Damned noseart up and named mine tc.bmp.... then i could view them in the TA).
Hope this helps you.