I use these techniques on planes that are fully sheeted and fiberglassed.

Panel line s and rivets done in the primer coat, once the surface is ready for priming.

Lay out the panel line s using a flexible plastic rule and a pencil, working from your reference drawings/photos.
Work on one major surface at a time (lower wing, upper wing, left fuse, right fuse, ect.).

For butt joint panel line s, use 1/64" chart tape and lay the panel line s out. Use a high build primer. Spray several coats over the tape line s, feathering the primer towards the center of the panel s. Once dry, remove the tape. This will leave a groove in the primer. The adhesive will tend to stay in the groove. I use a small scraper (grind a small hook in the back of a #11 blade with the tip broken off) to remove the debris. Lightly sand with 320 grit to get rid of any roughness.

For lap joint panel line s. Use painters masking tape layed out on the low panel along the panel line . Spray several coats over the joint, feathering the primer towards the center of the high panel . Once dry, remove the tape. This will leave a ridge in the primer to simulate the joint. Lightlysand with 320 grit to get rid of any roughtness. For thicker overlaps, such as around the nose fuel tank on a Spitfire, I use several layers of tape, and instead of primer, I use auto body spot filler in a tube spread on with a small plastic spreader (a phony credit card works well). Once dry, remove the tape and lightly sand with 320 grit.

For flush rivets, you need to make a special tool made from brass tubing. You need to find a way to attach a 1/16" brass tube to a soldering iron (in my case I used a trim covering iron and nestled tubing up to the size that fit inside the mounting tip).
After you have primed the plane you can start the process. Lay out all the rivet line s and rivet spacings using a rule. Now press the tip of the tool into the primer to melt a ring into the surface for each rivet. Lightly sand with 320 grit.

The plane is now ready for color coats.

Scott