I do a bunch of laminating of carbon fiber and Fiberglass cloth.
Another recommendation for Gingher.
I honestly thought these would have noticeably dulled by now, they have not.
https://www.amazon.com/Gingher-8-Inch-Knife-Dressmakers-Shears/dp/B000UU6SR4These have very fine microserrations which do not push the material being cut infront of the blades. Locks it in place and just cuts it cleanly. Very impressed.
Running a fresh razor blade along a straight edge has not been a successful method for me on fiberglass of carbon fiber. Usually it just screws up the weave of the cloth.