I visited another shop with a bandsaw to separate and trim the rudder parts I had marked. My fellow builder and I decided the bandsaw would be good to separate the shear clips and attach strips, but we pulled out a pencil-die grinder with a metal cutoff wheel to trim the stiffeners bottom rib and rudder horn brace. I did not have any issues with the cuts, and managed to color outside the lines!
I took the parts home and started the process of filing them to the final cut-line. I found that clamping the part to the table and working lightly with a flat file allowed me to get the part to the final cut-line very accurately.