Very interesting, I have no doubt that the wood surrounding the adjusters are strong enough judging by the inserts imbedded into the handle where the hard points insert. My question is How do you keep the hard point inserts aligned on the vertical plane with each other other than the locking thumb wheel screw. I would suppose you could torque the independent hardpoints out of alignment, which could cause weird response.
This is very similar to my handle which I made years ago and still use as I carved it to fit my hand. On mine the hard point is a bar that attaches to the top and bottom thumb wheel dajusters via a pivot point top and bottom. (Imagine a Giant Clevis that the threaded portion of the adjuster attaches to)