The best suggestion I can offer you Rara is that you look at all the hardware options you have to choose from and make the best call from there.
Your suggestion on how to get around it on a 'one-off' are fine but as you suspect this just ain't gonna fly trying to sell it to someone. Way too much work. Trust me; it's hard enough to get some people to figure out how to do a simple bolt up, let alone let them loose with a grinder...lol.
I can't say I really have much interest (nor the need for) helping on it. It's the same problem if I tried it. Even at that, selling a dozen sets of brackets wouldn't come close to compensating for the time on them. I'm sure you're figuring this out too.
You do the leg work and if I can help you on the mfg, let me know.
