Not sure if I can give any meaningful advice, but yeah, I've sanded necks to change the profile. They came out great. Isn't really rocket science. Just be sure to check often to make sure you're not going too far on one side (unless an asymmetrical profile is what you're going for of course). It's really going to come down to judgment. But with patience you should be able to accomplish your goal. To make a significant change you'll have to start out with a medium or heavier grit and once you're getting close start switching to ever finer grit. I spray several coats of lacquer on mine, fine sanding between each and finishing with rubbing compound for a factory gloss. But that's a personal choice. Many prefer an unfinished neck.
Of course I'll be very surprised if you don't get a bunch of "just buy the neck you want and keep the original for resale" type responses here on ever "resale mindful" TGP. But I'm more interested in making the instrument work for me.
I was in a local pawn shop not long ago and on the wall was a 2002 PRS CE-24 that was a little road worn,dull finish and tarnished chrome,but the owner had sanded the finish off the neck and it felt really nice.The associate noticed it and thought it was just worn off from playing,anyway the asking price was $800 and I offered $650 because the neck was worn and he accepted...hahha
I tried to sand an unfinished neck I have. Just took 600 I think. Used my hand and slid up and down the neck like I was playing. Held the sandpaper in kind of a U shape trying to follow the old back shape. Then used 0000 steel wool. Feels sooo good now! It wasn't the shape I didn't like. It was too fat! So it worked great for me!
I had an old Fender Lead II. I guess the neck finish was polyurethane? Anyways, a little heat from a lighter would cause the clearcoat to literally peel off in large flakes. Probably not something you want to try, but it was incredibly effective.