It would also help to know the diameter of the larger piece. You may be able to go straight to the band saw mill without chain saw milling it first (my Norwood can handle up to 34" diameter logs). 2tree's advice about allowing 6" trim on the length is good. You could also cut them 8'6" and 12'6", if that meets your needs better. Most woodworkers would cut the 12' logs in half anyway. I've found that with careful cutting, I can yield about 40% quarter sawn lumber without sacrificing quantity, though it takes longer to mill. If you can find a local sawyer that you can work on from the start, you'll be ahead of the game. Only other advice is to not hang around during the milling process. Otherwise you could get hooked on it. It is too late for me... Good luck, & be careful!