One option, if you have (access to) a 3D printer is to use that to produce a QR. I've got one I've printed (but not yet assembled -- too little play time) and it seems significantly sturdier than what came on my partner's cheap aluminum tripod. I'd want to do some tests before trusting it with my RB67 or Graphic View II, of course, but it's almost free (consumed only fifty cents or so of filament and a couple steel fasteners).
No springs, uses a cam lever to lock the camera plate into the mount, and nice aggressive dovetails. And if you need more plates, just print them.