You've got to be pretty well forwards towards the section of the hull with the most rocker. Hans can get these things to tack pretty fast! Of course, with all that sail you've got you could just about tack it with one hull still out of the water....

That G-Force 21 Grand Prix beats up on all the boats at the Olympic Triangle races held in the bay. He finishes the race, furls the jib, and has a drink while waiting for everyone to finish. Hardly ever has to get out on the trapeze wire, either...

David,
The mast bend inversion is caused by the big overlapping jib on your boat in high winds. Here's what happens: The forestay sags; the mast leans forward due to the sagging jib luff and this pulls the jib leech tighter. In this situation the jib is just pulling sideways and backwinding the mainsail like crazy. This causes the mast bend to invert if the spreader tips are not 3 to 4 inches behind the mast. With the spreader tips well aft of the mast sailtrack and looking at the mast from the side, tall slender triangles are created due to the spreader sweepback which push forward on the central part of the mast and prevent mast bend inversion. It will not prevent jib backwinding; that takes a small high aspect ratio jib like you see on most beach catamarans. The rig, large overlapping jib, that you have on your G cat is a light air rig only.
Good Sailing,
Bill