How are you deciding when 24 hours have passed? When the transaction is sent, or when the transaction gets 1 (or X) confirms? What times are you using - the "time" given by a third party service like Blockchain.info, or the block time, etc etc?

Why would I bet anything more than 0.1 BTC again?

How are you going to handle purposefully unconfirming transactions?

Are you running this off a separate wallet?