The research that I have done so far as led me to think that the best way to cut sheet glass would be with a diamond wet tile cutter
I wouldn't recommend this at all. Being a tile setter, I work with wet saws all the time. I can tell you that 95% of the time they don't cut square, also it can be very difficult to put a large piece of glass on the table and hold it there to cut it. I think the best way would be with cheap glass cutter, a decent tape measure, a framing square, and a straight edge, depending on sizes of the cuts you want to make.