I had to make a stop that would fit under the saw as it slides so I made a box that could easily be clamped to the saw's fence. It's made of cherry because that's what I had for scrap.
I made a hand clamp for when I need to cut the boards vertically because they are twice as tall as the saw's fence and I needed to have them as stable as possible.
I made the hand clamp by cutting a cam like shape (increasing the radius from the center point) in the end of a long board. Worked great. It pressed the board firmly up against the lower part of the saw's fence and kept everything as solid as I wanted.