I used to cut all my drywall sheets on the floor until a foreman in Tampa showed me a better way.
After he saw me struggling with a 12-foot sheet last month, he had me set up two sawhorses and cut on them, which completely eliminated those annoying edge chips and saved my back.
My first try looked like a beaver went at it. Chips everywhere, jagged edge. Total mess. Finally caved and got a proper pair. Night and day difference. Should have just listened to everyone from the start.