Hello,
to hand shape foils...
draw a center line all the way around. also draw a line on both sides where you want the max thickness. Make a few templates of the foil you want at different spots up the length of the blade. this is to check your progress.
i once got the foil in jpeg form off the internet. next i redrew the foil in a vector program and outputted it. use your "eye" when shaping.
styro core foils for a cat are a pipedream in my opinion. once you get enough material on for the skins, the foil will have changed too much. that's if you could get enough material on there. also you need solid glass or carbon in the center for the tip, leading edge, and trailing edge. then there are somtimes holes in the blade to deal with as well.
you can layup a nice blank on a sheet of glass just using tape or weights without using clamps. clamping strips, normal wood working style is good too. especially if you have a planner.
cheers