Guys I'm gonna recommend biting the bullet and stocking up on a few spare parts. A set or two of extra blades and grips, feathering shaft, linkages, etc. Build up a crash kit - you're not doing yourselves any favors by having to wait on parts. If you consume some of your kit, re-order just what you use. BUT at least you can still get stick time while parts are on the way. Other than the blades its not too costly for the other head components.

And the really weird thing - once you get stock of parts you may find that you never need them... don't even try to figure out that one...