The normal arrangement that John is describing has the leaf springs attached to the back in the center of the spring usually with a rivet that has large flat heads, and it is free to swivel. There are grooves in the inside edges of the frame, and you push the ends of the leaf spring into the grooves as you rotate the spring to hold the back in place. This mechanism is fairly quick to operate, so it is easy to open half the back and check progress when printing out and close it again as needed without disturbing the registration of the print and the negative.

There is one downside that your design alleviates, which is that with extremely long exposures, the rivet can get warm and leave an artifact on the print, but generally one learns to avoid such long exposures. On the other hand, with a spring that is held in place at the ends as yours appears to be, I would be concerned about the spring bowing up in the center and not applying enough pressure.