Custom Weld-in Firewall Strengthening

Here is the finished work. The following steps will show how I went about making these plates and welding them in. This project came out a success. Flex was reduced considerably (tremendously even) in the pedal and brake area. I used 18ga steel. Although less welding would have sufficed for the job, it is also important to consider using continuous welds to protect the vulnerable gap between the plates and the firewall from the elements and future brake fluid leaks.
The cardboard template pieces and the plates that where cut from them. They were pretty straightforward to make. I made the top plate first, then clamped it in place to create the lower template.
The starting point. The firewall had a coat of undercoating that had begun to fall away because of the brake fluid dripping from the cheap brake fluid reservoir I used. Next step is to get it to bare metal.
Got it down to bare metal, looks pretty good. Some minor rust that will be chemically treated before I weld the plates in. The underside of the plates along with the firewall will be painted and the area to be welded wire brushed to clean metal.
Creating the lower template in this picture after having cut the piece for the top as mentioned earlier.
More fitting, pretty happy with the cuts. Had to make some minor trims to the pieces as I usually like to make my cuts slightly larger then what I believe will be the required fit. The lower plate has the pointy edge on the right hand side. It fits in place smoothly and I wanted to include as much "flat area" as I could.
Here I am fitting again after having cut the bolt holes in the top plate. Every minor change that is made you should fit the pieces again. So cutting all the bolt holes in both upper and lower plates at the same time is not recommended.
Swish cheese! After having cut the bolt holes in the lower plate I decided to drill holes for the spot welds. A few of these holes where made prior to this repair and will be filled in.
In this shot I have already drilled the hole for the brake fluid reservior, finished drilling the lower plate bolt holes, primered and painted the area the plates will meet the firewall. Also doing another fit measurement with the bolts tightened.
Here is a back shot of the area. You can see I have not yet ground down the ares for the spot welds. The large hole in the upper left corner near the bolt is where the relocated speedometer ran thru. I will fill this in as I am going to use an original 140mph / 8k dash cluster this time around. :)
Almost ready to weld here. Spot weld areas are clean metal and I have installed and tightened down all 8 bolts that will run thru these plates.
The front flex plates right before welding.
After welding and grinding down the spot welds. The front pic you've already seen at the top. Hope you find my little project helpful!