You DO have some options, too:
First, you could do a little rewiring, so one flipper button will fire both (four) flippers.
Second, if you don't have anyone to help modify the game (not that difficult - if I was up in your area I'd do it for free, and make sure it's reversible), you can try contacting Ted Estes ( check_switch_26 ) and see if he would be a standup guy and forward the custom H8 (I think, may be an earlier version) software he made for a friend with the same issue.
In either case, good luck! It's a gorgeous game, from what I can see.