Tim,
That is certainly a creative bit of tension, that would definitely require tertiary training
I have got the Tubb one, that costs about $250 here in Australa, on my McMillan F Class stock. It is adjustable 3 ways for a better fit, which all sounds fine, but in my case turns out to be wasting money.
I only use the LOP adjustment, to shorten or lengthen the overall length , which is easily done via an external fitting.
It can also be adjusted "left or right" for about 0.5" either way, as well as vertically for a bit over 1", but the fittings for those two are blind, accessed by pushing an Allen Key in through the 1/2" of black rubber on the butt plate itself. They are such a pain in the arse to adjust, that I have stopped using them. If the vertical is adjusted upwards, which is ideal for prone shooting, it is then very much in the way when cleaning.
So I am wasting 2/3 of my money ! Based on a bit of hindsight, I would recommend that you look for one with simple "Length of Pull" adjustment.
Tony