I know from hanging around a lot of painters and body shops, and also painting a quite a few cars myself, that colorsanding single stage is not generally a good idea. The part of the resin system that provides the glossiness migrates to the surface of the paint, and if you sand it away...
The term "die back"comes into play,.... means the paint will dull when you remove the UV and the gloss enhancers (actually a "clear" part of the resin that migrates up). And then you wind up having to polish more and more frequently just to keep a shine.
Don't get me wrong, there are some who do it ever slightly, and maybe they can chime in, but the axiom for a painter using single stage is; "What you spray is what you get" and if there is excessive orange peel, runs and a lot of dirt in the finish etc. you pretty much have to block it and repaint. In other words, you could wetsand the S/S just fine, get it to look as good as it did coming out of the paint booth, but if you've cut into the surface gloss good enough, expect to have to buff it out again in a couple months, whereas the shine you have now will stay there (albiet with orange peel) for a few years if cared for, without excessive polishing. Tough choice I know.
This is why base/clear is the preferred method of most DIY'ers and shops, because you can wetsand out runs, remove orange peel, and make a bad spray job look downright show-like (if you've got enough clear on it). Not so with S/S.
Here's a good forum on auto body where most pros reinforce this opinion, (you'll have to search for posts on single stage yourself though-no search function and I can't link to posts in the archives it seems) and it has a lot of good info on paintwork;
http://www.autobodypro.com/wwwboard/wwwboard.shtml
Best of luck
