I LOVE this ruler:
Wing Clipper 1 - Deb Tucker's Studio 180 Design (deb-tuckers-studio-180-design.myshopify.com)
It trims multiple sizes. You can use whatever sewing method you prefer (8 at a time, or individual sky and geese like Bonnie Hunter does). Then trim. I typically do the Bonnie Hunter sewing method with the triangles cut just a wee-bit oversized.
I think there is also a Wing Clipper II that does bigger ones too.
Wing Clipper 2 - Deb Tucker's Studio 180 Design (deb-tuckers-studio-180-design.myshopify.com)
I purchased mine directly from Deb Tucker.