Dave...
I really should have paid attention while photographing the blocks, there are two force blocks and they are directly opposite one another thats the only way they work. I posted this same thread on another site and everyone commented on how this set up would not hold the angle block and HSS spacer, i only threw them on the face plate for a visual... alas they are correct, these little blocks would not hold this set up and i did not intend them to hold items like these of such height.
I did not make them exactly to Harrold halls print... i just was in the shop and machined on the fly as that is a normal MO for me to do, i must say (howsitwork) comment on the screw height is correct, none the less these blocks will work fine for what i need now and i am going to size the blocks up and make another set for different size work, these are a must in your tool work holding crib.
God Bless..... Anthony.