Thank you! I'm sure I could have been more productive over three days with no work, but I think this was a good amount of productive for me.

Sheet straps/garters are amazing. I've got three sets going right now: One set for the mattress cover at the corners, one set at the corners of the fitted sheet, and the set that's attached to the pillowcase. I was pretty upset when just using the first two sets didn't prevent the middle of the sheet from bunching up, but I'm quite glad that my workaround is working decently. Probably less trouble than using just a full mattress cover sheet or something, where you pull it over like a sleeping bag and zip it closed or whatever, which would have been my next resort. Or at least less expensive than finding at least two of those in the right size, should they even exist.