dunnnce, that last picture of yours is very interesting.
Where the pivot plate is, you can see daylight through the whole back half, so all of the pin weight is on a small area at the front of the plate. That has got to create some extreme wear issues, and demonstrates the very high forces on that system. I take it that there is a wear disc in there? I imagine you will be changing that quite often, otherwise it could get real sloppy in a hurry.
I know that this is supposed to be the cat's meow for those who don't want a slider, but it looks pretty darn scary to me.