Should have said something earlier..
I work for a glass company and deliver all over..when I saw the cutting of that windshield I was hoping I wasnt too late...The tip I got was to use a glass cutter,even a cheap one.Score the glass lightly and keep it straight as possible.flip it over then follow the score on the other side..trying to match the one on the other side as best as possible.NEXT..pour lighter fluid over it and wait until its almost burned out...SLOWLY..and I mean SLOWLY bend the glass down...NOT all the way though..if thats not working,re-heat it.You should be able to bend it enough to get a glass cutter or a VERY sharp razor blade in between the cut...slowly cut until your done...you may have to re-heat if your working slow.The glass used in laminated safety glass...Two pieces of glass with a very thin sheet of plastic in between them.