stripping poly finish from a strat body.

I've never stripped poly but have read of anything from the aforementioned heat+putty knife to Aircraft stripper. But I wonder what the downside is to sanding it back to say 320 grit and just paint over any finish.

I don’t know anything about this kind of thing, but why couldn’t you just use a palm sander and sand down to the wood?

Yeah, very tough finish, lots of dust. The biggest mistake I see in the sand-it-off method is the body not ending up flat. If you get a bunch of divots where you sanded more aggressively it will look awful, and possibly not be usable. We had a customer at the shop bring in an old stripped Squier body, and we gave it back to him because the area around the bridge was so distorted it wasn't going to assemble correctly. I remember putting a jack cup on there, and there were gaps you could fit a couple stacked quarters in. I think the neck plate area was all jacked up, too. Obviously whoever did that just didn't understand what he was doing well enough to prevent it, but if you're going for hours with an orbital, it seems like patience would run out and it would just happen.

I've never done the heat gun method, but knowing how hard it would be to sand that would be what I'd try.

I wonder if using a planer would be an option for the flat parts of the body? Sure, it may lose a tiny bit of material, but at least it should not cause that kind of distortion.

You can then use another method for the sides.

I haven't used planers enough to say, but knowing how hard/brittle/weird poly can be, it doesn't sound pleasant. Best case scenario it would be really messy. I've seen some people use a thickness sander, if it is wide enough for a guitar body. If it was me, I'd start it with an orbital/whatever you're using and do the last bit in the thickness sander since those sanding pads are cheaper.

It could be kept flat by hand, you just need to be aware of what you're doing. If a person goes in hyper focused on just getting the finish off and doesn't check stuff along the way, it is going to get screwed up. When it has looked horrible, it has been probably because it never occurred to them as they were going along. Plus, as the finish disappears, the changing appearance will tell you how evenly you're sanding as you go through color, primer, and so on. Peegoo made himself some sort of tool/jig for really getting bodies flat, maybe it was just a level with sand paper stuck to it. a piece of high quality ply turned into a long sanding block with some handles attached could work as well.

I was a long time ago, but I remember using a wire wheel and some paint stripper. Got down to bare wood pretty well and even.

I think another factor is how you'd plan on finishing it. A solid color is one thing, but who knows what horrors lie beneath, like a mismatched 5 piece cutting board.