If it were me doing this project, I'd do the Pillsbury crusts since they are inexpensive and you will need many of them. Who is is footing the bill? The majority of your time is going to be spent paring apples and slicing them. I've done this with my children and my husband's granddaughter and it is very time consuming since they tend to be fearful of the vegetable peelers, don't hold them properly, get tired of working, spend a lot of time giggling and talking, et cetera. You're very time-limited, so I don't think I'd even fool around with a crust that wasn't pre-made. Rolling them out will probably be challenging enough.