Truthfully I prefer light parasol. It gives much more height and some good aerial momentum.
I have tried out both Light Parasol and High Parasol. Light Parasol is no good at all. The Up B itself has not hitbox. The only hitbox that's protecting is when the parasol is open but that's not nearly enough to cover her. Besides, you will have to close the parasol in order to get any range out of it. All of this leaves her very vulnerable. It was incredibly easy for my opponents to gimp, they didn't even have to try. One running Bair off-stage or Dair etc. was more than enough to kill me.
High Parasol was better than I thought. Now I'll admit my opponents didn't always actively try to abuse High Parasol's weakness and aggressively edgegaurd me, but even when they tried they couldn't succeed. High Parasol is really fast. Like mentioned before, it's similar to Rosalina's and Pit's UpB. Despite the fact that they're slower and sometimes even miss the ledge, even these UpB's tend to go unpunished often. Peach's UpB may not change the angle as freely as they can, but it's A LOT faster and thus much harder to gimp.
However, Default UpB's recovery is already pretty good too. When using High Parasol, I went for edgeguards a lot and I would often make it back to the stage safely. However, each time I made it back with High Parasol I felt I also could have made it back with default Parasol too. Default Parasol has very some decent range after all. Besides, even though I don't use UpB as a killing mode very frequently, I still do use it on occasion so it's a nice tool to have. I'm not sure if I'd like to give that away.
Nonetheless, I support High Parasol. Peach's edgeguarding is pretty strong. By using High Parasol we may find even more powerful edgeguarding set-ups that could boost her game. Having a higher recovery could definitely imrpove her game in certain aspects. I think there are a few sets that use Light Parasol: I would suggest to at least replace Light Parasol with High Parasol.
The only custom I would use in a custom environment is sleepy toad. Peach's other moves are already good on their own and better than the alts imo.
There is a set that uses 2111 but it really irks me. IMO Sleepy Toad is not even that much better (if better) than Toad because of it's horrific frame data, but that is arguable. However, even if you would find it better, wasting one set for only Toad does not seem like a good idea. Toad is still just Toad. None of the Toad are good moves (it's a counter after all). Peach has a lot of interesting customs, she can't afford to waste any slots.
(This wasn't specifically directed to you btw. Just kinda crossed my mind))