Best non-slip rubber for handstand blocks?

[Tyler Phillips]

Hello everyone! Not too long ago I had some downtime at the woodshop I work at, and I was able to build my own handstand blocks after eyeballing a design online and reverse engineering them with a bit of guesswork for some things like the downward angle of the blocks (10 degrees is what I settled on that felt best). They came out great and they're very sturdy and comfortable... except when I try to use them on my hardwood floor they slide! haha 

I'm asking you all what the best solution to that would be. I was thinking some kind of non-slip rubber flooring material since it would be low-profile (1/16") and I could get it cut to the exact size of the base (10" square). This would be better than typical furniture sliders since they're higher profile thickness (lowest one I saw was 1/4") and don't cover the entire base surface area. Thing is I don't know what rubber would work best for the underside, although I know I want a firm rubber with no give and potentially a bit coarse to prevent movement. For example I see on Home Depot there's 60A Textured Recycled Rubber at $1.88/ft² which is amazing for the price... but would that work for what I want? Idk much in the realm of rubber materials. :/

Any help y'all could give here would be greatly appreciated. These blocks came out great for a first-time build and I want to get busy with using them without putting down a towel or something all the time as a quick fix.

Cheers!