Lower Wheelhouse Replacement Part, Is it meant to be single layer, or double? Options

[Gudhjem]

I’m working on repairing the area below the Hell Hole – basically the bottom of the passenger long around and behind the jack post.

My plan is to preserve the double-wall original aspect, so I’ve been taking pains weld new metal onto the inner C-shaped long pieces before I repair the outer pieces that sit over them. TIG welding on slightly pitted 20ga is challenging, but I’m managing. I’d rather not go the single-wall replacement route that the RD/AA inner long piece for the engine compartment is designed to do (the one with the corrugated ribbing that shows after install).

As part of this, I need to replace the metal around the jackpost on the inner wall. I’d like to be able to use this piece from RD:



Can anyone tell me if the RD piece is meant to go inside of the outer long (like the original configuration) or if this is meant to be a single-layer piece, with nothing over it? I'm guessing it's meant to be single, since I think I see a flange on it, and the inner "C" channel pieces don't have that. I’ll have to do some pretty tough fabricating to get the jack post hole right...

[TargaToy]

I ordered the wheelhouse from RD. I had it a little while (still working on the driver's side) and happened to notice on someone else's post that their part had the second ply. When I contacted Mike at RD, he sent me the inner part no charge. I'm presuming that the two pieces are supposed to be one unit and some were shipped as singles (by mistake??).