KerchCherry, are you able to make your bots trade with the scrap.tf bots?
On scrap.tf you can trade a key for 19.44 refined, which is a fair price. You would then have a more precise currency available for balancing the bets, whenever you had keys you needed to divide up.
I have something similar in mind (yet much easier). I've already done like 80% of it in the past 3 days, should be done tomorrow evening. It should balance payouts better without a need to trade with external services. I might only sell earbuds manually since they are relatively high value, but there is no need for keys really (unless future proves that I'm wrong ;)).
Also I would be surprised if they were allowing botting their service considering how they are always out of stock on keys.