Re: OMC tilt clutch pack
If you lock the entire clutch mechanism together, you remove any ability for the drive to "give" in the event you hit anything substantial. If you do hit something, the possibility for doing some serious damage to the tilt mechanism, intermediate housing, engine or stringers (in that order, roughly) is greatly increased.
I definitely recommend the washer method or a new clutch pack (if you can find/afford one). The tilt mechanism on the Stringer is (in my opinion) the absolute worst part of the entire Stringer system.