With the armor I pull on my vacuum table, I trim it down with a standing belt/disk sander. If you don't have one I believe harbor freight has them for 40-70 it would be worth it even if it's a one time use. I built a clone with out one using just tin snips to get close and then finishing with sand paper and that was really tough. I'm sure there are other ways to do it but in my opinion the belt sander is the easiest.
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