You should consider doing away with the conversion to USD. Doing so creates extra risk for your company that is really unnecessary.
As an interested party in the same industry we feel that if we can make your company stronger than it will protect (y)our customers and make the Bitcoin gaming sector stronger as a whole.
Again doing away with the conversion to USD will alleviate all of the downside risk you are experiencing. Leave player deposits in BTC and take your profits and convert them to USD or your currency of choice (or leave them in BTC) according to your risk management protocols.
BTC withdrawals of over US $50 will be batch-processed daily at 3pm GMT. Lesser withdrawals will be processed as quickly as possible, usually within 1-6 hours.
This is a ridiculously long time for a Bitcoin withdrawal to be processed. As quickly as possible should be less than 1 hour and really closer to less than 15 minutes. It is tough to understand why it would take until 3pm GMT or 1-6 hours for withdrawals to be processed if all that is necessary is for the USD you have on deposit at one of the exchanges to be converted to BTC and either withdrawn to your wallet.dat and then sent to your customer or sent directly to your customer from the exchange.
We have found that Bitcoin users expect near immediate deposit and withdrawals and we feel that someone should be able to get a withdrawal as fast or faster than they can make a deposit. Comparing yourself to online casinos that deal in fiat currencies and stating "most casinos take days or weeks to process withdrawals" is very misleading. We average less than 10 minutes for withdrawals and since we are the only comparable casino that deals in Bitcoins we take a little offense to you stating that most casinos take days or weeks to process withdrawals.
Online gaming may very well be the industry that sustains the growth of Bitcoin in the near future but as an industry we need to try to do better than just outperforming existing fiat currency casinos.