I made a little spreadsheet with the speed tiers for all (Max EV, Nature) Touhoumons.
https://docs.google.com/spreadsheets/d/1BkFHzMDoYZ6U9bF7n-_XQnfOQWz0s87BOwFnQFwdPY0/edit?usp=sharingAs far as I know, the formula seems to be 5 + 2 * Base + EV + IV, where IV ranges from 0-15. This means your stats should be one point higher at lv. 100 than the equivalent Pokemon stats. This comes into play with rounding at times for looking to outspeed things.
The way to read the spreadsheet is to look at the column. For example, let's take a Speed Shinki which uses Intimidation (Known in regular Pokemon as Dragon dance or DD). It's got 95 speed, filling that into the ' my speed' box gives us a base of 225 to start with. If we want to outspeed everything except weathers, sakuya, and aya at +1 speed we need 271 speed. So a speed EV of 46 is good enough if we want a SAtk nature, for a spread of 46 speed, 64 SAtk, and 20 HP to outspeed most stuff after a single use of Intimidation.
Note: There might be some commonly competitively used puppets that will reasonably always run less than full EVs and no speed nature. In that case it might be relevant to include the specific case as another tier, but it is simply to early to tell what/when will happen, so only the 'max' speeds are included here.