Bill, I made them with Henry Atherton doing the fabricating. (he made most of the Safir tubs at Adams Mac in High Wycombe)
Gary- no problems at all. Notice that there is rod ends (spherical joints) on the hook set up triangulating the side plates.The front frame on the GTD with aluminium panelling both sides glued on and then avdel riveted is incredibly strong and there is no flexing at all. For a tow hook I will simply bolt a dural plate on the side of the left lifting hook.
The bar thats you see on the jack is stainless - I think 25mm or 30mm with a boss to sit in the centre cup on the jack and two stainless endplates to sit just outside the hook and prevent it/them from moving around as you jack it up. I'm not sure it Pat Barry made something similar.
As for the rear end, once the ZF trans is installed, there will either be another jacking point on the rear, not disimilar, or I've been looking at some air jacks that the Audi R8.R10 uses - just simply shove the airline in and voila. QED or W5
regards
Dave.