but 1300x1300 is bigger than 1800x800 and the wrong shape!

My material comes 2800x2070 and will be sawed into smaller rectangles for me to collect and put on my cnc. The biggest shape that I need to cut is 1650x670.

I don't have the need (or room or ability) to handle anything bigger than that. I did choose 1200x800 based on it being 1/3 of a standard sheet, which is a nice size to collect from the local B&Q.