I'm answering it here because it doesn't really belong there.
It's tricky. Suppose you deposit 100 CLAM and a minute later I withdraw 100 CLAM. I'm going to get the 100 you deposited. Should you have to wait 4 hours before you get staking rewards? I don't see why you should. The full onsite invested amount is now staking... I have things set up such that new deposits are used to service withdrawals, and so there's never a huge amount of coin 'waiting' to age.
It's almost always true that the amount of coin in the wallet that is waiting its 4 hours to start staking is smaller than the amount that is in people's balances but not invested. So you end up getting more than your fair share of the reward anyway.
I don't like the idea, and it would be a real pain to implement. Currently I don't track each investor's balance, I only know what percentage of the total bankroll they own. We can handle 100 bets per second because each bet only has to update the site's bankroll, not 200 different investor balances. If each investor had a different range of bet sizes they were willing to get involved with it breaks that scheme, and I have to update all the investor balances for all bets.
What's your motivation for suggesting such a scheme? How would it be fair for you to take all the nice low variance bets and leave the more dangerous bigger bets to other people? I don't think it would be.
I agree with the stacking system, investors have the advantage of getting stack rewards 24/7 and the stack reward on clams that are on the balance of players? By the way can you confirm this last point?
Could you tell me approximatively the average total balance of players for the last 2 weeks or now? I understand it must fluctuate a lot.
The motivation of suggesting such a scheme is that some investors are interesting about having a return with low volatility and some investors are interested about having the best return long term even if it means having a small risk of losing most their investment.
Allowing investors to choose the max profit they are "playing" would allow the prudent investors to have steady returns and the others to have a bigger return (if whales don't get lucky). I understand why it would be technically difficult to do it.
If your CLAM are only used for bets of less than 1 CLAM you would likely win everyday and if your clams are only used for bets of less than 10 CLAM you will likely never lose a large portion of your investment.