>> would 4mb of extra ram make a big difference?
If you possibly can I would try and get a 1230, ideally a Blizzard with a few megs of ram with it. It turns the 1200 into a really handy machine and with WHDLoad is pretty much the optimal setup for running classic games.
Also for Wing Commander I strongly advise you to get the CD32 version and run it with the excellent WCPatch from Aminet, it speeds things up a lot as well as correcting some bugs. There's a couple of reviews documenting the differences on the Amiga Games Database.
Also, if you like this kind of game my personal favourite is Star Crusader (also reviewed) well worth a look.