It comes down to how much you need to be making from each of the IC so you can keep you facility open. Also, are the IC would be training any of your existing clients or will they be bringing in their own? This could affect your decision on the amount of $$ they will be paying you too. You can check what other studios are charging, but each studio has different operating costs. So, again it comes down to how much you want to make and cover your costs as well. It also depends how much they are charging per hour for their sessions. You don’t want to make it very difficult for them to make a living, so it has to be fair for both of you. You can charge them a % of what they make or a flat fee.
I don’t know if this answered you question, but I hope it helps.