I've never seen a Starfire canopy, but unless it's very thick or stiff, R/C car (lexan) shears - the ones with the curved tips - work great.

If it's brittle , very heavy or thick you can use a Dremel cutoff wheel. I usually outline the canopy cut line area in masking tape and then use a thin point magic marker to draw on the cut line, usually + 1/32'1/16" or so then sand to the final line using a sanding block and 150 to 220 grit.

Barry