Good luck with the 880. Your going to have plenty of power and bottom end with that amp. Just as long as you don't have to move it.
Not to be negative but I would of chosen to go the Powered Pa cabinet route. A pair of good quality 12" or 15" QSCs, JBls, Yamahas would be more versatile. You could spread them apart for a better stereo sound and even put them on stands. Nice to be able to take one home with you for a gig or practice. I'm using a pair of JBL 515xt cabinets that are only 32lbs. but they can handle anything.
Have fun with your new setup. Definatly pull up a pipe organ patch with some heavy bass pedal sounds and raise the roof !