Recently tried the StarBrite Waterproofing. This is the only product that states on the label that it works on Sunbrella that I’ve seen besides 303. Seems to work well. Water beads up, doesn’t wet through. Less $ than 303.
This time instead of spraying I applied using a sponge type roller and a brush. Roller disintegrated, so I finished the job with the brush. Less fumes this way it seemed.