[EricH]

Originally Posted by squirrel

1/8" is what you want, no need to go to too much trouble just to make it adjustable.

How much drop you put in depends how much rock you want/need. I can't remember offhand how much 330 drops their center, or any other recommendations (I'd say 3/16, but that's way too much--more likely 3/32 or 3/64.)