I did my own made from .040 T3, because that is what I had.
I used my English Wheel to shape them and to roll the flange. Three times was the charm as my metal forming skills needed some developing. So be prepared to scrap parts and start over.
I have seen others that where done with a shrinker/stretcher but they did not turn out as well, not that it can't be done that way.
I coated the back side of the fairing with Sika before riveting to form a seal and wipe the excess off to form a filet. Worked well and looks professional, or at least as professional as an amature like me can make it look.
I made the choice to go metal because I did not want to bond plastic to metal, not for service reasons. All of the plastic parts on my airplane are either screwed or riveted on. I have seen some bond thier windscreen fairings as a separate part and they look good too.
I like to see rivet lines, and separate parts are just that, separated. That is a personal choice, but not a popular one. People go to great lengths to hide rivet lines, fair in and fill tips, etc.... to get that smooth sleek look. That is just not me.
A side benefit in a metal windscreen fairing on a slider is that you never worry about a passenger using the roll bar to exit or enter the airplane, even when I ask them not too. They are very rigid.