Bruce, I was always impressed how you car guys get the finish so smooth. Feel like divulging a few tricks of the trade??
I do have a few car kits on the shelf, but that requires a change of thinking from the past 20+yrs. Not saying I won't ever do them, I'll just have to make a concerted effort to get in the proper frame of mind, as in, glue marks, clumsy fingers, and what else to avoid, ya know.
Note: In reference to your question about sanding the seem off "rubber" tires, I remember reading a blog saying to place them in the freezer for 15-20mins to get them just starting to chill hard, then sand lightly. I haven't tried it yet, so not sure, but I think Rinaldi or Bryan K does that trick for the running wheels on trucks, tanks, etc.
I start out sanding the bare plastic body of its parting lines, sink marks etc. Down to 1000 g wet dry sandpaper..prime with Duplicolor sandable primer and sand it smooth again..Then colour coats..knocking down any dust specks or orange peel between coats..usually 3-4. Then decals..then clear 2-3 coats.
On this WR1 I used Tamiya spray paint and it laid down so nice I don't think I will need to clear it after applying the new decals..we will see
I find it is always good to stay within the same manufacturers product lines as far as primer, paint, and clear goes.