Do you have to move money around much? How easily do you dry out the funds from one of the accounts?
Yes, a bit. Usually have to transfer USD once or twice a week, and will move BTC a bit more often. But sometimes I just wait for the spreads to flip around and do the rebalancing for me. The Paxum fees hurt the worst and I dont transfer to/from it unless I've made enough to cover it.
Bitinstant looks interesting but there seems to be no way to get money out of TradeHill, so I might start using it as an alternative to Paxum for TH deposits and continue to use Dwolla for Gox and CampBx.
Do you have a "minimum profit" or do you arbitrage as soon as you cover fees?
Yes, I have a min profit $ setting and also scale the amount I'm willing to trade against a minimum profit % (with commissions factored in) and never attempt to trade the entire lot size...as it's too easy to get left holding one side of the trade or the other.
I also make sure to do the sell side first and if that was successfully executed and fewer than a certain number of milliseconds have elapsed since the order book was grabbed, I proceed with the buy order. I've gotten burned a couple of times with a trade here or there that didnt fill, but all of them eventually cleared out with the volatility over a few days.
The funny things is I expected under capitalization on my part to be the limiting factor, but I rarely see spreads where I'm not able to cover 90% of it. I hope to be adding some rules to the engine soon that will search areas of the order books rather than just the current lowest ask vs. highest bid and that approach may show that my adding more capital might improve the returns.
