Constructional Criticism Please :)

[Steve Chryssos]

Norm,

Regarding the load the UCA will see makes sense. The back seat will not be used do to the roll cage and other reasons. Perhaps I should think about tying the roll cage in to the mount. A Y coming off the middle cross bar or the inner bars that run from the main hoop to the floor.

Both are probably too far forward. If you've bailed on the driveshaft hoop idea, and you are incorporating a roll cage, then you're on the right track. Don't worry too much about reinforcement for now. Get the pivots properly located and the reinforcement will become obvious. Maybe an upper crossmember tied into the rear down bars of the cage with a vertical mount that drops down to meet the third link--plus triangulation from the upper crossmember to the lower crossmember.
Whatever--you won't know for sure until you finalize the forward pivots.