I have my S-21 tail feathers built but nothing assembled yet, and it seems to me that painting those first makes a lot of sense so we don't have to disassemble and reassemble later. Could also balance the elevator if we paint now. Others tell me it will be impossible to keep the paint blemish-free after painting and to wait. Is there a consensus from those who have done this before? Has anyone used an automotive paint shop for at least base coats on parts? Is that worth considering?
We always paint before final assembly, some parts, like the cowling and boot cowl we paint after fit up. Those parts are trim to fit parts. Vertical, rudder, horizontal stab and elevator are not and can be painted prior to installation. The only time we install them on a fuse is when there are stripes that run through them and they need to carry on from the fuse through the vertical and rudder.
There are also many guys that like to fly before painting a single part on sheet metal airplanes..
I've used automotive (base/clear) on fabric and metal with good results. I've found it much easier to paint before assembly as it is double work to assemble, disassemble, paint and then reassemble. It isn't hard to keep from messing up the paint on assembly, you just have to be careful. You could test fit everything to be sure prior to painting, but I have found that to be not necessary with Rans kits. You should think ahead and if you see a future issue with fit and paint during assembly, then fit everything up to be sure. Hope this helps!
I have used auto paint on fabric with good results, several times.