I think that I've corrected my rectal-cranial incursion. The SST/FSM's resulting number is how low the knuckle is sitting. NOT the shim thickness required. It is mostly semantics, but it is important to my way of thinking. A negative number means that the knuckle is low. A positive number would be mean that the knuckle was high. With no shims installed it would be really hard to deal with a positive result. A negative result is easily corrected by adding shim(s) (adding a positive to a negative moves it closer to Zero, right?). I've had to modify my own checking tool (POoR link above) to work with the seal installed. I hope to be able to check the DS tonight. If my (new) thinking is correct, one of the thickest shims moved from the top to the bottom should put the knuckle within 0.001"-0.002" of being on center.