I TIG welded mine the full length (sides) and the tabs. If the parts are fitted close you can flow the metal without using filler rod and yes, use stainless filler rod.

I would not waste time or material trying to solder it. You could braze it but it will not look very pretty when finished unless you wire brush it then toss in the tumbler / polisher for a while.

If you cant find anyone local to TIG weld it for you I will (for free) if you want to mail it to me.
I am getting low on shield gas but should have enough to do a small job.

You really do not need replacement weldments, once yours are properly welded they will not break again. Use the $$$ for something else you really need.

I welded one for Pinster (rgp) for his TAF, it's a common problem for weldmets and not just TAF.