I have just cut my windscreen of my Heritage Classic. Followed the instructions on several websites it was even more easy than expected by me. I have applied self-adhesive paper tape as used in paint jobs to protect the glass of windows instead of the advised plastic tape.
First of all I made a carton model of my new windscreen, appr. 2,5 inch lower than my existing windscreen. Of course I had measured it first if this cut would be sufficient. I covered both sides of the windscreen at the place of the cutting line with self-adhesive tape. On this tape I marked the cutting line with a ballpoint. Because of the firm paper tape the line is excellent visible.
Took a SHARP new fine cutting saw and laid the windscreen with the outside up on a plastic beer box. Fitted excellent with the stainless steel supports and laid very stabile. The cutting was easy, take the time to let the saw do the job and don't push but 'steer' the electric handheld jigsaw.
After the cutting job I places the windscreen on the bike again and sandpapered the cutting surface with a type 80 sandpaper, wrapped around a small piece of wood. After removing the raw edges changed to type 240 sandpaper for the finishing touch.
Took the windshield off again and washed it with fresh water to remove the sanded material. Result: excellent and saved appr. 275 US for a shorter windscreen in appr. 1 hour of work. I cannot earn so much money is such a short time.

 

Good work. It sure is gratifying when you complete a project yourself and it works!

 

You just finished a true 'custom' modification. No one else has a wind shield just like yours, and you did it yourself - the very definition of 'customizing'.

 

Take a propane torch and Burnish the edge for that factory edge look. Dont linger and watch what you are doing and it will tell you when to move on. Practice on your cut off first.