Having gunite done tomorrow and the high temp is going to be like 111* here in PHX tomorrow and I'm the 2nd job so probably 11-12ish start time...I'm a little nervous. I'll be on a strict watering schedule for curing.
Keeping the new shell watered after will be the chore. As stated above, when the plaster gets done will be key. Job should take 3-4 hours and if temps and direct sun are the issue, inquire how they will "tent" your pool to slow down curing time.
It's fine they will adjust the mix and you will be on water duty. I've seen a hose bib timer setup on one of those light spray sprinklers do the watering automatically. Plaster is another story as said