I would use something other than SS plate for that repair, if you were going to proceed. How about
G10 plate? That is a dense and very strong fiberglass laminate, available in almost any thickness. You could sand the original shell and epoxy it right to the original glass, then paint to match. The advantage over SS plate is that it has the same stiffness and thermal expansion characteristics as the original structure, will bond very effectively (much better than SS), and very likely look better when done. Can be bolted and/or screwed too.
