Thanks for the replies -- it will be on site, so I won't have access to my bandsaw. I was thinking about the aluminum blade for the TS55, but was concerned that the relatively greater hardness of the copper would toast the blade. For whatever reason, they don't maker a steel blade available for the TS55.
I like the idea of the plywood sandwich, though, and think I will try that. The metal shears may be a second option -- but the cut is pretty long and the edge will be exposed to view, so I want to get as clean a cut as possible.