I have the same rack from Princess Auto, kinda the Canadian Harbor Freight. Side note, I find it difficult not to write HarboUr...
I used mine numerous times and had similar issues to you folks. Borderline acceptable welds, rattles like crazy, etc.
I haven't used it much except for transporting empties, or to pick up great curbside garbage day finds (I like to resurrect old stuff). Since using our tent trailer more these days (similar to a Heilite), we wanted to carry a 10lb propane tank, some sceptres, tool box. Check it out.
I basically flipped the orientation to make it work best, then cut some relief spots so it would sit flat on the a-frame, then fluxwelded, sanded and painted. I can jump on the corners with very little flex...mind you...I only weigh 155 lbs soaking wet.