I didn't like the contour of the clearveiw windshield so it I trimmed it. I used a 1/4 inch air die grinder and a cut off wheel , if you don't have air tools a dremel tool should work, it would just be slower. I used an electric random orbit sander with 22 grit to get it to the final size and shape, then hand sand with 400 grit and a flexible sanding block until all the scratches from the 220 are gone then finish with 800 or 1200. Cover the entire top side of the screen with blue painters tape you might cover the other side with tape too. I just laid mine on an old pillow.You can always take off more putting it back is tough. Once you make the rough cut don't touch anything but the edge. Unless you would like to learn the fine art of polishing. Good luck.
Personally I wouldn't even atempt it with a hacksaw. Sounds like a pain in the ass to me.