SprayTech, If I haven't learned anything else on this group, it is that no two painters use the same process.

I use 36 or 40 grit on a vertical sander to strip paint. I can strip a full size car in 3-4 hours, or I can strip a set of bike tin in about 10-20 minutes per piece. no chemical residue, no warped sheet metal, no doing bodywork over, Just metal prep, prime heavy and block with 360. I don't know if you enjoy sanding, but I use the heaviest grit that will not give me problems later.

BTW, I hated Feather Fill too!

Most of what I've learned is self taught over a 40 year career. Classroom theory, and manufacturer's recommendations are fine, but for me, it's a reliable process, and as few hours as are necessary to get the quality I need. I do only custom work, so the standard has to be pretty high. If it didn't work for me every time, I would have already changed my methods!