Did a lot of internet window shopping back when shut-downs began. Heaviest-duty Racks I see from various manufacturers all seem to use 3" x 3" 11 gauge steel, although 2x2, 2x3 and 14 gauge is out there too on cheaper stuff. Different companies and different price ranges use different hardware also. There may be some in-between sizes I'm unaware of, but all I've noticed is either 5/8" or 1". Rogue for instance offers a line of Monster Racks and another line of Monster Lite Racks that seem pretty much the same ... all that differs is the hardware, and the price. I guess "bigger is better" is a good general rule, but I wonder if the price difference is justified for us average gym rats who don't Bench 500+ or Squat 800+ ?
Another variable out there is steel spotter pins vs. the nylon strap ones that came along more recently. Offhand nylon doesn't sound as reliable as steel to me, but some of the Rolls Royce caliber stuff made by Rogue, Sorinex, etc. offer it, so ... ?
Biggest variable has to do with timing vs. investment. If the damn virus does go away to your satisfaction, or to your gym owner's satisfaction, or your Governor's, will a somewhat limited garage gym get ignored once you can rush back to all the extras a good commercial gym has? How much money are we willing to risk on stuff we might not use much in 2 or 3 or 6 months? That "availability estimate" in post #29 above says August, for example. Happily assuming "August" holds and doesn't become "Fall," it could still be late August ... 3 months from now you will have paid for stuff you don't have yet, 3 months from now closer to your old Gym re-opening, if it hasn't already.