I have for my Bessler MX a mounted Scheinder 135mm for 4x5 that is fitted with an adjustable lens board from I think the old Zone IV Studios. Its a two-part board, with a large rubber (?) piece in-between, and three screws connecting the two boards, which then allows a micro amount of adjustment for the lens to Neg stage. It seems pretty well thought out, but I don't do much 4x5, and according to my Veraslab Laser, it does do what its supposed to do. I think some good ideas are yet to be discovered in alignment.