I'm going to go through some of the Pokemon that outspeed some 90-100 speed Pokemon, as that is a very good speed tier for PU. Basically, if it can outspeed a base 90 pokeymans in webs, then it'll be good. They will have max speed and a speed boosting nature too. So, imagine togedamaru. If it runs max speed and jolly, it has a speed of 320. So, 320 multiplied by 2/3s is 213 (rounded). Doing the math, I got around 50, however, that only outspeeds togedamaru. We need to see if there are other pokeymans that we can outspeed. Ribombee can actually be outsped at above 67 speed. Ribombee is obscenely fast, so I would say powerful wallbreakers above 67 speed would do the trick. As sumwun said, you want ot be able to check the dangerous Pokemon, however, in my opinion, anything above 67 speed, which includes 69 (nice).