I wouldn't combine them into one auction. That creates the impression that it's a blow-out sale, and you'll take what you can get. Buyers expect a bargain when they bid on multiple items as a lot. Also, buyers may already have one of them and not want to pay very much for a second copy. I would list them separately with starting bids of about half of what you eventually hope to get. If it doesn't sell, relist it at a lower starting bid, but not too low. Or, you can have a reserve price. There's a lot of psychology that goes into selling on eBay. Have lots of photos so there are no doubts as to the condition, any flaws, etc. Good luck.