I removed 3/16" from a huge piece of 1/2" starphire. The glass shop cut it too long to fit into my stainless steel frame, and I didn't want to have to cut and re-do the frame.
I used a cheapy water cooled tilesaw, and actually cut the amount I needed off the very heavy sheet of glass with no help. (looking back, I should have waited for someone to get home to help hold it steady
)
If you happen to have one, just set the fence and go for it. It cuts through glass like buter.