cat 1 on a cat 2 tractor. my first re-action. is the cutter heavy duty enough. and are you more likely to just tear up the smaller size cutter.
other words.
--cat 1 stuff, tends to be lighter duty metal, gear boxes tend to be for smaller size tractors.
--cat 2 stuff tends to be heavier duty metal, and gear boxes setup for higher powered tractors.
did a quick google search for "gannon hitch" and selected images as results.
going to assume long haul you would be better off modifying the 3pt frame on the cutter for size needed for your tractor.
or sell the cutter you have now. and spend the extra for a larger size cutter that your tractor will be able to handle. perhaps bat wing style ((double decks)) bush hog / rotatory cutter.
or look for a different cutter. that might be easier to weld on some tabs or extend pins. that connect to the lift arms on tractor. and same for the top link.
if ya posted pictures of the hitch on tractor and setup on cutter. folks might be able to help ya better.
also if ya posted make/model of tractor and cuter, folks might be able to help ya better.