I was under the impression it's similar to anywhere else in the resort in that it ranges. CRs get 20+ hours/week, FTs get 30+. You can have anywhere from a 4-8 hour shift, with the option of calling to pick up more shifts if they're available and you want the hours.
"Remember 'Old Yeller'? We shot the dog." - Roy E. Disney
The hours if you work third shift custodial are pretty regular. Well, when I worked there they were, but I doubt much has changed in less than a year.
Usually you get in at about 12:30 am and clock out at 6:30 am, and once you've passed the probationary period (about 30 days) you'll be offered the option to extend your shift to 8:30 on certain days. Sometimes they'll even schedule the full eight hours.
you'll can usually get about 5 or 6 shifts a week.