Hot off the press, here's the prototype of the "Plow adapter" for the compact tractor Quick Hitch. The design is already slightly changed from this one, but you'll get the idea. The subcompact QH design will be coming along shortly.
There is no hydraulic connection yet. Two hose extensions are in the process of being made which will run along the loader arms. Also, thanks to a thought from KennyD, the hydraulic lift cylinder on the QH will likely be replaced by a solid link. The cylinder being in place won't be optimal and is easily removed.
Range of motion with the dump/curl active:
Doing a bleed down test on the disconnected dump/curl (no movement in 20 minutes)
An unforeseen additional benefit, being able to favor the plow to one side.