Hey Richard (Ay ... can I call you Ray?),

We don't wear neckties....ever!

Miss Itchy, good point. However, the ones that would put a shim in to reduce the bottom gap, are probably the same ones that forget to pull the travel stops on springs. And I've seen too many springs with travel stops not removed to worry about shims.
_________________________
Richard Havard, P.E.
Piping Engineer
Wood