I like your mounts! Got a couple of questions, though.
It looks as if the point of contact at the upper would be at the fixture for the arm. On my Mark VIII setup, the point of contact is on the arm just outside the pivot. There must be a difference in the frame width at the lower edge between the uni's and my '66, or between the Mark and the cougar stuff. I have previously measured t-birds and Mark VIII's and found no discernible difference.
I have the same ride height problem currently. I need to come down 4 1/2" inches to match the front with the Mark lower arm in original position. The only area of interference to drop that much is that upper control arm mount (easily fixed), and the rear mount point, which will require modification to either frame or mounting, or both. I'm shooting for 2 1/2 to 3 degree pinion angle, which will duplicate OEM.
I am also looking at my options for the front mounting. I don't like the original mounting arm; and it would prevent use of a side-mount fuel tank.
I am considering fabbing a square tube crossmember and utilizing the vertical mounting points at the third member with a pair of urethane insulators.
Final question involves wheels. It looks as if you've solved that issue on your mock-up by simply eliminating the lug nuts
Are you running a universal pattern, or utilizing the original patterns, or modifying the hubs?
Thanks for any input!
Paul