email robertson stykbows and ask.
personally, at that kinda bow weight i don't think the connexion hinge is viable unless the riser is laminated with a very hard wood that's well accented with phenolic, and the back of the bow, where the hinge goes at the riser area, is also beefed up with at least a layer of phenolic or carbon as well.
i have a tembo blank that i'm doing up with a connexion hinge and i purposely went with the strength and hardness of cocobolo for the riser. also, i will not recess the hinge into the bow's back as that will compromise the limb/riser integrity/strength.