The pixel floor can be even thicker too, up to like 15 pixels.
Also, kami can fail in another way: if you do kami standing on land that's 17, 33, 49, 65, 81, 97... pixels tall (every 16 pixels), kami will leave 1 pixel of land on the left and right sides (with no floor). So basically, it's good to have your opponent fall through the center to be safe, because it's hard to tell where those heights are. Replay here:
Another way to look at it: there's a 6.25% chance your kami hole will have those single pixels, so plan accordingly :0