Erik, thank you, I've been repairing and restoring my whole life!,...when I was younger it was out of necessity to keep the drums I could afford up to playing level and as the years have gone by I learned most everything by trial and error and not always to positive results! The bottom edges were in bad shape with 1/8 inch gouges from no bottom heads, the the tom banging on the kick lugs and the floor tom was sat around and moved etc,...without the legs,...my guess.
All my pics are on a digital camera I'll find some and get them to you or post them,...but,...heres the rundown,...I use a piece of a Formica laminated counter top for sanding and leveling ( I need a piece of granite! ). I use two way tape to hold down the sand paper on just the outer edges as not to create an unlevel surface. A trick I use is to take a carpenters pencil and cover the bearing edge completely, when sanding keep checking for pencil marks ( low spots ), when all of the markings are gone, your there.
Then like yourself I do a 45 at many passes and checking each time for correct amount, on these right up to the inner ply, if that makes sense, years ago I thought one pass would be fine and went deep and chipped, ripped a shell badly, beyond repair.
Then a round over on the outside, I hit the edge very lightly with a rasp and then sand lightly, I generally wipe them with some tung oil to finish them off. On these 3 plys it just make sense to get as much head contact as possible for the great tone and warmth they are known for.
Now with that said, on this kit I adjusted the edges ever so slightly per drum on purpose. Meaning, the tom has the least of round over, the floor tom a little more and the kick even more,....my thought process was:
Snare=all attack
Tom=less attack
Fl. Tom=even less attack
Kick=no attack, nothing but boom,...the attack comes from my foot and beater
I'm no rocket surgeon but this tonally made sense to cut them accordingly,...right or wrong, that's what I did and it worked great in my opinion,...they sound just as I planned.
Your process seems to be better,...I'm just a poor boy making his way,...oh! and keep in mind this is a players kit, my playing,...if I were planning to shelve these things I would have went completely true to specs etc,...and all that jazz,....