To bad your not closer, I saved my old screens for bits & pieces for 'X'.
You could stop in a hardware store or glass shop and ask for scrap plastic. Explain what you're doing, they might even show you. One did decades ago for plate glass edge finishing.
It is easy to cut a plastic windshield. The tool you'll use most is patience.
3 ways to cut Plexi or Acrylic. No matter which method you use, finishing the edge is required.
There is a special scratch awl made for plastic.
__ Takes a long time due to many multiple passes.
__ If the scratch is not deep enough, a running crack has a high chance to happen. To thwart this, cut/scratch both sides.
__ Slowly bend back & forth to weaken the cut area until it snaps apart. You'll hear it start by it's minute crackling sound.
__ Duct tape both sides of the cut. Preferably 2 layers, one on plastic the other on the saws base plate. Be sure to plainly see the line. Light from below is best, it will glow.
__ Use a new blade with offset teeth. Go slow, let the blade work and do not force the blade, force produces heat by friction. IF you're still concerned about heat, use compressed air on your cut and blade while cutting. It also keeps your line cleared to see it.
Portable Power Plane.
__ Twice now I have had wonderful results but be sure it has a sharp blade
. Big plus is you'll be moving faster than a jig-saw there will be much less heat. Test by feel on every pass.
__ Keep a firm hold on plastic and planer or it'll chatter and problems arise. (I know this from my wood working days and hard woods)
__ Make minimal depth passes. I've never had it happen but too deep a cut will chip plastic and possibly have a running crack. Molded/formed plastic (and glass) has internal stresses waiting for the unsuspected.
__ Using this will create the edge near finished. Just a little water wet sanding (grit steps - 320/400/600/1000) will beget a foggy see-thru edge. Going 2000 grit will be glassy clear. You can dry sand but the paper will clog up necessitating cleaning. Quick rub on your pants removes a lot to keep going but not all.
A new file will cut the edge much quicker than sanding. This will help you get really close to your line before wet sanding. You might even like the finish it gives.