After a lot of welding and grinding back, the bracket is more or less the right shape, with the missing material added back.
I also have a three pronged approach to locating it in space, relative to points on the frame, along with an angle “tool” which I created while building the RD250LC.
Bolting the jig to the frame, and adjusting the angle showed me where more grinding and welding was needed to fit snugly against the frame rail.
…and it’s done.
Not my prettiest welding, but it appears to be STURDY!
Whether it is at the right angle… well that will have to wait until the rebuild is done, but it can’t be worse than it was before.