Richard,
From the pics that I have of the Ryan it looks like the aluminum panles on the Ryan are butt joints and do not overlap. To simulate this I put down 1/32" or 1/16" chart/drafting tape. Once you have the tape in place where you want the panel lines spray a couple heay coats of high fill primer such as Dupli-Color high fill primer then sand the primer down to the top of the tape and remove the tape. This will leave you a very nice panel line, add rivet details and paint.
I have done this on several planes with great results.
Anthony