When I was still shooting in 8-ball leagues at a place in Herndon VA (Breaker's Billiards, "In the Clock Tower!"), they had all Connolly Ultimates, 6 legged Chiricahua model with 2 inch slate - all 9 footers of course. Connelly boasted of 5 bolts per rail. I believe the claim was, other things being equal, the tighter the rail is to the slate, the better/faster the ball is off the cushion. When you mention changing the floating nut plate on GC's, would that impact performance in like manner?
Also, I've been notified I can finally start donating plasma again (tomorrow), so I'll have to see how fast i can bank some more restoration money and make a decision as to whether or not to have the subrails extended sooner rather than later. I wonder what all that weight would cost to ship. Walnut is heavy.