Keep in mind that the "rule of thumbs" regarding shims are just that. The OM606 is much more sensative to shim thickness. For example, the OM617 rule of thumb is .05 = 50 PSI. That may be accurate in some instances, but not all. The OM606 may mean .05 = 100 PSI. You will need shims ranging from .025 or .0001" and up. The various shims come stepped in either .10 or .05 increments. Unless you luck out, you will need a lot of shims to get to where you need to get them at 2,000 nominal PSI +/- 50 or 25 ...