I had to cut some glass from a roll of a different type of glass, uni directional. In places where there are particular loads uni directional glass has all its strength woven in just one direction instead of 2 directions in double bias (or 3 in triaxial) glass. The weight of the glass is 450g per square meter but would be twice as strong as equivalent weight double bias in the direction of the weave but half as strong as the double bias across the weave.
I used my temporary cutting table (sheets of mdf, over sheets of duflex on 44 gallon drums) and hauled over the 50kg roll of 450g uni glass. The roll is 1220 wide. I rolled out the 6.6meters I need and cut it off the roll (I think the roll is 50 meters). I then marked out 300mm and cut if off the length, then I repeated the process making another 300mm width length for the top half of the forebeam and leaving a 620 width that I will use on the outside of the beam. I rolled each of the lengths up ready for use.