Currently as is, the game counts a max of 6 boosts per profile, one thats worth 10% and five that are worth 3% each. I feel as though that is a bit disappointing seeing as if the rest of the people don't inform you or already know that they will only contribute 3% instead of the standard 10%. Seeing as you can have 6 people boosting at once, I don't think it's all that unreasonable to want more than a 25% boost, and honestly maybe even have all 6 count their 10% because for example in eggwars the max discount you can have is 60%