Hey Terry, I think most people misunderstand this process, ...and quite honestly I used to also.
When you read the Service Bulletins and understand the instruction, the process is
not to shim the Flywheel Housing into alignment, ...but the indicator is used to just check the FW Housing to verify it is in alignment. The only place that shims were allowed is in the upper two holes, -and this was to compensate for the gasket thickness. If installing a 0.010" shim in the two holes where the tabs are did not bring the housing into alignment, then Ford specified to install a new housing. New ones are available today, -or some original housings can be machined. I modified a grinder by installing a large faceplate to be able to re-machine a flywheel housing where both sides are coplanar. Click on the link below to see what is happening;
https://youtu.be/2GDg5AT2TmI