TRD Pro Skid plate square washers

I found a used TRD Skidplate locally for sale. The seller said it was only missing 1 bolt. I picked it up for $100 because one bolt & spacer should be easy to piece together at the Hardware store. After I brought it home I checked out the install instructions online only to find that I’m also missing 2 square shim washers! I’ve already contacted the seller and he said he doesn’t have them so I’m SOL. I don’t really want to spend $90 on the hardware kit when I’m so close! I think this is something I can fabricate on my own with a piece of steel and an angle grinder but I don’t know the dimensions.

1. how critical is this piece to have an angle?
2. If it is a necessary part, can anyone share the dimensions?

Thanks to @ChunkyToy for the pictures (copied from another thread).


Installation Instructions:

http://toyotaparts.sparkstoyota.com/install/PT938-34140inst.pdf

 

After doing some measurements and cross referencing the size in ChunkyToys photo, my guess is it is a ~1.75 to 2” square. I’m not sure of the pitch though.