i used 2 arrangers (korg and yamaha) while one played a midi file, i was set up with a style on the other and ready to go into the next song. my longest time i did this was 4
hours. my total investment was less than 2000.00 for both keyboards and not that big of a problem setting up or tearing down.
OR you could go with a laptop for midi file play back with an arranger.
good luck
dave