I'm not familiar with any use/abuse-to-destruction tests, and based on my experiences with these guns, they are probably all pretty close. In real-life use, you're not going to "wear-out" a frame on these guns, nor is frame stretching an issue with large magnum Ruger revolvers. Finally, if unsafe-pressure ammunition is your concern, the cylinder and/or barrel is probably your weak spot for bursting strength instead of the frame.
If pressed for an answer, I'd say the Super Blackhawk due to the simpler machining and symmetrical geometry of the frame's shape.
I have a Redhawk that's 25+ years old and it has seen some idiot-fringe loads from an inexperienced-but-learning handloader (), and I still have all my fingers.