By absolutely no means do I consider myself an expert metal fabricator, but I think I’ve come up with a solution. I’m currently restoring a genesis platinum 1, and I obviously ran into the same problem. During the restore, I replaced the flavorizer bars. When I got the the bottom tray issue, I tried my hardest to find an aftermarket replacement but it just wasn’t going to look “original”:
I then came up with the idea of taking an old flavorizer bar, hammering it flat, cutting it with a pipe saw and attaching it to the shorter genesis silver bottom tray on either side. It fits perfectly in the existing Z bar bottom tray mounts. It absolutely isn’t pretty or OEM looking, but the additional stainless covers any gap that might have been present, and it’s certainly a snug fit.
If anyone is interested, I can show what I did via posts, but it’s pretty self explanatory and in the “early stages”.