Originally Posted by
Mike Mills
I think this will be a problem for you when you use the bike, so be ready for it. Professionally made bracketry is usually stiff, either from having out of plane stiffening formed into it during stamping or from being made from thick, stiff material.
Because you are fabricating a one-of bracket (like I also need to do), you can either bend the edges up to create stiffeners or you can secondarily bond stiffeners onto your flat-pattern bracket (use epoxy for adequate strength and weather resistance).
I especially liked this bit of your post, thought-provoking stuff for makers of one-off hardware and brackets. Two other possibilities for adding stiffness to brackets might be adding a twist of up to 90 degrees or using a bead roller to put a stiffening rib into the flat stock before forming the bracket.
And OP, that is a seriously beautiful bike. Well done!