Related suggestion, to speed up fin cutting, along with templates:
If I have simple fins whose edges are straight, I usually cut them out well outside the final line, and not worry about cutting them precisely. I then use a small tabletop disc/belt sander to sand the stack down to the final outline. Even with curved edges, if you have a narrow enough belt, you can follow the curves.
All fins have super-straight edges, all identical, and really fast to make.
My hobby belt/disc sander is a Dremel table top model, with a 5" disc, and a 1" wide vertical belt. The narrow belt is really a great feature. It is perhaps one of the most used power tools in my shop, with maybe the exception of my drill press.
By the way, I use a hobby bandsaw to rough cut my fins, most of the time. After I get the typical 3-4 cut, I stack them, and either cut along the fine lines on the top fin, or add a paper template, if I really feel the need. If the fins all are aligned on a sheet, I can usually cut out all the fins in less than a minute. I'll zip the first one off the sheet, then the next, and so on. Then I run all of them thru for the a 2nd cut, then the 3rd, etc.