i saw this at the hardware store and gave it a go, on my ws board and sup.
This stuff is about 1/2 as gritty as monster traction paint, which is not that grippy either. id put it at around 220 grit. with booties on it is barely noticeable. on the plus side i shook on a little acrylic dust onto the wet clearcoat which now seems ok. the final thing i want to mention is it is not really clear, in fact it is pretty yellow so if you spray it on a white board you will get a nice placquey look. overall score 3/10.

does the monster traction paint stay more clear then the rust-olium?

it does stay pretty clear, it was on my board already and i noticed immediately when the rustoleum stuff went on over top. i've only seen the monster stuff at island surfco.