I don't think that I can specifically answer any of your questions, but would it maybe be useful to you to have two Amigas with MAS players. You could have one playing and queue the other up. Perhaps some simple script could be written that would even allow for control between the two Amigas via ethernet or serial cable.
Maybe overkill, but heck who wouldn't want two Amigas to jam on?
By the way can anyone tell me if the MAS palyer is still even available? All of the links that I've looked at appear to be dead.
Regards,
AmigaEd