I wonder if drilling small holes in the original deflector would help? It would allow some of the heat to escape upwards instead of all being deflected down and out. On my GS the coolest temps at grate level are in the center, temps get progressively hotter to outsides which range between10-15* hotter.
It may be easier to remove it and replace with something else like it sounds like he is going to try. I have not paid too close attention to mine, but I can see what he is showing.
The original measures 8" round. The struts underneath channel the flame forward to some extent. I do not wish to deform or alter the original. I have two choices to pursue:
1. Leave original deflector and insert a baffle between the flame and the affected floor area. could use just a piece of sheet steel laid against the side of the tunnel on the floor. elevated by 1/4 inch air space (just use nuts as spacers). Probably the easiest thing to try and it would probably work fine. However, I don't really like the idea of deflecting heat downward onto the structures and tunnel. Seems like it would waste energy and accelerate decay.
2. Have ordered 9" square of 3/16" thick SS. Will mount 1 hex head SS bolt 5/16" and 6 inches long on each corner of the sheet and use it as a standard 4 legged deflector. This is about the height of the dome of the current deflector. (I first thought of using 3/8" bolts but decided that it would be overkill). Will then do test runs and adjust the position as I did with my old Traeger deflector to get the most even heat distribution. I suspect it will work fine. I will remember to plug the holes where the original deflector is mounted, so as not to lose air flow to the firepot. Will report after completed. Will take a while to get the stuff.