Hello, first build about to go down. I don't have a metal cutoff chop saw. I do have a mitre saw, maybe I can use a cutoff blade? How about a hacksaw? What are you using?
The chop saw will work fine. Either use a fine toothed carbide blade or an aluminum cutting blade. I cut aluminum with a 60 tooth carbide blade quite often. Just take it slow, it spits aluminum sawdust all over everything.
mitre saw is perfect for cutting it. It is what the manufacturer of my extrusions uses and you will see same setup in shops that cut profile for aluminum window fabrication.