Now I can see another fashion revived - the metal (alluminium) caps of the wishbones. Can't really see any point in those besides the longer life of the wishbone cap itself. And even then, having in mind that the pins are the most common problem, I don't really know. And let's not forget the struggle when you have to deal with the cap welded by the sea to the ring. Besides, they scratch the tube of the gun.
God, reading that brings back memories...I switched over to band guns from pneumatics in 87-88 and I think I experienced just about all the wishbone problems you did.
I included an image of new ones and some of the old ones I could find. The ones in the center are older ones, the stainless wishbones with the stainless couplings which as you mentioned tore the crap out of the barrel during the shot

turning your new gun into a used one quickly, but hey they looked and felt great new! and eventually they spotted with rust if you didn't keep them clean or worse they corroded like you said. The wire coat hanger type, those are cheap but only good if you use one 16mm band or a weak band as they bend easily and the only way they don't break over time is if you have perfect loading form which the beginners who use them don't. If you bend it too much or strain it eventually always breaks...Then came the first good articulated wishbones with delrin couplings but the shanks were too long so that most beginners without proper loading technique would strain to load them and pulling them incorectly would bend the shank (I did this too) as you can see from the one in the middle of the picture.
And finally they got better as the french articulated style design, that you see on the right, were made with thicker shanks and threaded with stainless nuts to hold the delrin couplings. These catch the shaft very well, don't bend, are low profile and aid in sighting down the gun more than the other design and can even be taken apart since they use nuts if one wants to mess around with a cord like I did in the picts. There are even short versions for people who use short bands and want the most power although it's harder to pull your hands out so I don't personally like those as much. Then the camo ones for the camo geeks
The two cord ones in the picture just haven't impressed me so far, I have yet to find a soft braided wishbone I like. One is 1200lb spectra braid cord-practically the strongest you could use aside from thick cable. The one screwed to the green 18mm bands are conventional production heavy duty cord used for speargun wishbones from another MFG. I use those types when I'm using multiple bands shooting bluewater fish like wahoo and tuna in the fall, so basically in less than two months I used those in the picts, probably about 5 outings and that's how worn they already are on Sharkfins.
It's amazing, we could spend all day geeking over wishbones eh eh. Maybe we should start the Encyclopedia of wishbones...
I'm glad to know the others like Roberto and Murat like them as well :wave
Mark
ps-Ivan the project is on hold and will take a few more months since they're redesigning a heavy duty rubber slip cover for the T-20 butts on the Master line to make it more confortable when loading multiple bands or without a gun chest pad integrated into the wetsuit. I'll send you an image.
ppa- sorry for the long post!