Oldsub hit the nail on the head, Colin wants to weld the OEM brackets back in the original location, problem is, they are castiron and if you never welded castiron, you won't know what we are talking about. It just dosn't like to be welded to any other metal or to it self.
Plus he wants to weld them only in the original rivit holes like a big spot weld. This would only be 4 spots less then 1/2" diameter each.
As far as adding late model stuff, thats a different story. Lots and lots of welding has been done over the years to frames with out problems. Done right, they work just fine. Joe