Sorry, I tend to think of the Gibbons and Gary Dierkings version of the Gibbons as two different rigs, My bad.The issues with the rig didn't really depend on the changes Gary made, IMO. I never sailed without a boom, but I fixed the mast vertically a few times with my original white sail. It didn't make much difference. The issues I had centered around a big sail swinging around one point of contact at the top of the mast. Making that point of contact slide around seems like it would not make the situation better.
But who knows. As you say, I used the Dierking rig which has a boom. Maybe if you try a boomless version it'll work for you. It's fun to play with, anyway.
I was thinking that when I pulled the tack forward and down to the bow of the boat it would pull the parrel tight on the (fixed) mast so the mast/sail connection would be fairly secure once tied down, but I see what you mean, during the actual shunt while the sail is only loosely secured at one corner it could get pretty wild in any more than a bit of wind, I guess if a fix was easy someone would have done it already.
I'll play around with the proa rigs and probably have fun, but I doubt I'll use them for anything but light air or spares, the Dierking/Gibbons looks like it would go together quickly and stow neatly.
After watching your boat I'm seriously considering putting in mast steps/partners in the bows so I can try a schooner as well, on top of fixing my balance problem being able to walk from one end to the other instead of scrambling across the tramp would be a huge plus with my bad back.
Is this you? looks like funMy Salamba, should push the limits of proa evolution. It has a full carbon rig ,new Blast sail, Harkin blocks and a windward skyhook sidestay on brails, that can tilt the mast to windward like a windsurfer. Might as well use the sail to lift the main hull out of the water at speed. I will keep. you posted. Health has slowed down my sail time, ,but this spring should be the bomb.