I’ve not actually used these that much, but I’ll put them up for ideas, anyhow.
I’ve made them a fleece outer with small sewn in sweatshirt segment as a “soaker”
I did an underwear style and a button up style- I much preferred the button up style (or pin style, in the case of the ones I never got around to doing buttons on), although I hate button holes. I reinforced with a no-stretch fabric on those that got buttons. I don’t know if it was necessary or not. I did a double set of holes for adjustability, but really don’t need the second set.
The underwear style I didn’t allow enough room in the back, so I had to add an insert in some of them to prevent “plumbers crack”
The legs seemed a bit tight in the underwear style. I tried one pair double layered- T-short inner and fleece outer, but they ended up too small and were hard to turn/finish edges. I didn’t care for them.