If the barn door type hinge for the bridge proves too wobbly, don't "give up". Just go to a common "piano hinge" (cut to length was a hack saw, etc) The width usually hold things straighter through its entire travel with zero play. Available "everywhere" from Ace to Menard's.
I've used them on large 6'x4' 1/2" & 3/4" wood cabinet doors used daily, leaned on, hung on, and otherwise abused. They are much stronger than they look, and hold the edges very well too, despite the tiny screws (drill extra screw holes and/or use longer screws if you really want to; but it's likely overkíll )
