That's a great site, Bullet! If you don't mind, I'm going to retype it so others can see it. Afraid you had a typo in your post:
Now, I just hope I didn't add another error.
I had a '54 hardtop. Although, except for the body and about 3 feet of frame rails, there wasn't much left that was Studebaker. That hardtop was a beautiful car, though.
Anyway, yes, the triangulated setup will not bind while cornering. And, you don't need a Panhard, which is why it was used in production cars (saved some production costs). My only concern was that it appears that the upper arms are angling up from the rear. Hard to tell from the pictures, though. And, the axle might not have been at ride height. If they are, though, this would mean you're going to be getting a lot of squat on acceleration. If you'll look at the cars from Detroit with this setup, you'll see that the upper arms are angling down.
I don't think I'd blame the parallel 4link for the "hop" you've seen on cornering. There's a lot of things that could cause it. If the links are truly parallel, there will be no binding and the car will corner like your triangulated setup. Don't misunderstand me! I'm not saying you should have used a 4link. Definitely not. You've got a beautiful setup for a street car. For that matter, it should do quite well at the strip, so long as the squat is not excessive. It does not, however, offer the adjustability which some would desire.