My reasoning behind the 90 degree bend is that the motion is closer to cycling
Sounds like a good way to blow out your knees. How do you figure a 90 degree bend is like cycling? My knees never get anywhere near 90 degrees. Well, on a BMX bike maybe.
Also, the forces on your knees during cycling pales in comparison to doing squats with weights. Just think of the thousands of pedal strokes you can do. Can you do 50,000 squats at a time? I don't think so.