A 2, 4 or Six slot would be your best bet. The older MV-1 boards have stereo capabilities and a socketed bios, go to hardmvs.com to see which one, familiarize yourself with what the board looks like and when you get to the auctions to inspect the cabs make sure the board is the one you are looking for. The newer MV1C and MV1B have soldered bios, so stay away from those if that's a concern for you.
As for the Super Auction, show up early and bring a notepad to take notes on what you're interested in and have an idea of what you want to spend and what items are worth. It's easy to get caught up in the atmosphere of an auction and spend more than you wanted to. Showing up early will allow you to get a good idea of what kind of shape the cabs are in. Some will be working 100% some not, but nearly all of them will be beat up, so expect to put in some work to bring the cab to showroom quality. All in all the auction should be fun, let us know what you come home with.
