Because the bolt goes though the two plates and draws the plug tight to the inner plate (with the ball sandwiched between the plate), the bolt should stay parallel to the axis of the bore when torqued. The eccentric nature of the plug and bolt will force the plug against the bore of the torsion bar tube if a couple is applied to the plug....but the two plates would have to rotate...the plates are bolted in at the 4 bolt holes.
Even the stock t-bar carrier end applies considerable force to the 4 bolts that hold the carrier plate...
With everything properly torqued I don't see how Mattias' design is any worst than the stock design.
Some other available options don't even have the plug...just an inner and outer plate....
If a road test or if nervousness requires it, here's something to look at....refine it for the application as needed.
