Last year I acquired a Landpride Quick Hitch for my 3 Point and had to modify my older Befco rear mount finish mower to make it compatible with the QH.
While Version 1 worked... I did not like how it looked and I really wasn't satisfied with it.
Here is the original hitch on the mower which had floating top and bottom links.
With version 1 I made the lower lift arm pins and top link fixed points and modified the rear lift arms to float.
While the deck would still float, it didn't cut the same and I wasn't really impressed with my finished product.
I returned the deck to the original condition and finished the mowing season with the intention of going back to the drawing board for a new solution.
What I've done with Version 2 is to copy the floating top link that is used on my Landpride Rotary Cutter and retain the original floating lower connections.
Now all I have to do is wait for it to dry out so that I can take it for a test run.
Perhaps tonight I will get out the floor jack and do some testing in the dry shop...