Second thought on this subject:
For a scooter windscreen you need two of this sets to get the whole surface properly done. I reglazed a GRAND DINK screen and had to do the inner side too because of microscratches all over.
Don't know exactely anymore, but took me for sure 3 to 4 hours of cleaning, sanding and varnishing.
The result was not 100% for it had very tiny bubbles at the edges ( not really visible, but..)
So, a new aftermarket piece from FACO or GIVI is here from € 85,- to € 115,-
-plus two sets of lens renewer cost around € 40,-
Overall a couple hours of work, IMHO it does not stand for, eben its possibly.
My resume: headlights yes, windscreens no.