I check valve adjustment regularly and have yet to change a shim after
> nearly 190K miles.
Cool, thanks much. Unless others note otherwise then I will just jump in and do the check without bothering with the tool yet. Sounds like they are pretty stable (I know that shim/buckets usually are), so I should just check regularly to catch any unusual seat wear & obviously keep the air filter clean and working so that I don't toast the valves with grit/dust.