FWIW. I did look at the picture, before ...
AND, I'm looking at it, now ...
IF you actually have the pedals AND you are talking about the
trapezoidal[COLOR= #ff0000]
front plate [/COLOR]of the cage onto which is shown (above) bolted onto the pedal , then I don't know why you can't just use the picture to recreate the
plate IF you have the capability of having it "machined" it BECAUSE you don't need to have taken a rudimentary drafting class at some point in your past to gauge the dimensions of the pictured plates ...
- its FLAT ...
- it is the same thickness "stock" as the rear plate ...
- the height of the plate is established by the pedal ...
- the width of the plate can be established by the rear cage plate ...
- and, the 'mounting' holes are where they are ...
- you can MAKE A TEMPLATE from a plastic laundry jug, or equivalent
IF you use the plastic template for a few rides, then you can determine how little weight the front plate is actually carrying ...
Regardless, if cosmetics are not an issue, then you can use ANY material that you want.
If, by chance, you are referring to something other than the trapezoidal front plate,[COLOR= #008000]
then point it out with an arrow.[/COLOR]