What diameter are those heat shields? 12.5"
Also do you worry about the arms that you have going out into the middle taking on too much stress from a brew put with 12-15 gallons of liquid in it? Since the arms don't connect to anything but the heatshield, I didn't know if they were at risk? I assume you know this to not be an issue or you wouldn't do it.
The reason I ask is I am in the blueprint stage of a single-tier 3 burner setup. I am using SS 1.5" square tube at 16 gauge. I cannot afford thicker wall. I am trying to think of a way of mounting 8.5" SS heat shields to the underside of the top of the stand. If I could just use arms like yours going out so I could weld the heat shields to the arms.... But now I wonder if 1.5" 16 gauge tubing could handle the stress load. The alternative is using angle braces in the corners that go out far enough to have a diagonal distance of 8.5". But that's much more steel.
Sorry to go off-topic. But you seems to know your stuff and are god-like in your skills.