Pretty sure that
@warp9.9 isn't small minded enough to not help you out. As far as I know the Rocket valves usually only tighten up though I am sure they could go either way. Too tight is a problem because the valves must seat to dissipate heat or they will burn out. If you use the
@Rocket Scientist method do not turn the engine over with a shim removed or you will chip the bucket( so I hear). Also use a micrometer if you need to measure the shims as calipers are not accurate enough.