- count up the occurrences of each species on each player's team, weighting using our weighting function
- empty slots get counted as well
- duplicate mons (or multiple empty slots) get multiply counted (so a team with one Magikarp and five empty slots will produce 5x the count of empty slots as Magikarp counts)
- At the end, you divide by the total and multiply by 6

As an example, imagine you're playing a tier without species clause. 1 in 100 teams consists of six Magikarp. Otherwise, no one uses Magikarp. Using the above system, 'Karp's total usage would be 6% (OU threshold), even though the odds of encountering a Magikarp in 20 battles is significantly less than 1 in 2.

So what I propose is this:

- count the number of teams on which each Pokemon appears, weighted by our weighting function
- divide by the sum of the weights of all teams