I'm installing crown molding at the top of the wall cabinets and ceiling. I'm going into a 45 degree 45 degree inside angle at a corner cabinet and to another 45 degree inside angle about 21 inches further. I'd like to put the 21" piece in place and cope in the two pieces that will butt to that. I do have a compound miter saw but the fence is to low to place the molding at a 45 degree against the fence. Can I lay the molding flat and set angles on the saw to get the correct results? Please advise.