Hi, John. I am confused whether you want to saw the 12" dimension or the 4" one. The 4" side should be easy to cut but if you want to cut the 12" dimension, you will have problems with throat depth. There are basically 2 different ways to approach resawing. You can use a tall fence and a wide blade, like 3", or you can try to hand control the inevitable movement off your marked cut line with a narrow blade. If you look in the latest issue of American Woodworker, for instance, they have a review of a cambered fence especially for resawing with a narrow blade. If your blocks and blade is set right, the 3" wide blade should not deviate much but a 1/2" blade will still wander a little, no matter how good your set-up. The simple answer for the narrow blade, of course, is to cut a little wider than your finish dimension and plane to the finish dimension.