Myred,
This all just reinforces my DIY ethic and lack of trust for any type of warranty. If you believe your design is the most durable and elegant and don't want to get hot and dirty, I'd suggest to hire the frame shop experts you trust. If parts locations are super-critical, mark the locations yourself. Not every welder can interface with a customer, a schematic drawing, and his clamps.
Jim's post and advice of bolting to frame has a lot of merit, got me to thinking about the layout of the brackets. Since you have a web truss frame, bolting the bracket through to an opposing side filler plate would add a lot of strength to the bracket and also develop better frame integrity. The bracket plate and filler plate could also be welded into place. once critical dimensions and operational function are secured. You could note that Northwood's shock bracket looks like it wraps the frame. If you do go to the bolt-through method, I'd suggest to add a sistered filler piece against the frame vertical for some distance from the bracket. This will help to spread the loads out into the frame from the single bracket location.
The additional back story of how the brackets had to be cut back out and rewelded into a better location adds some reasoning as to the quality of the work involved. Some guys get pretty frustrated when confronted with redoing their work. Doesn't excuse the poor welding techniques but does explain a possible scenario.
Good luck with a better resolution for the shocks.
