We have added 2 new exchanges to our vip crypto-currencies arbitrage software: https://bittrex.com and https://www.deribit.com
https://www.okcoin.com/ - will be added next week
Bittrex and Deribit crypto exchanges do not support market orders and support only limit orders. You can use limit orders and in this case you need to spesify slippage, but you also can to imitate market orders and in this case you need to select market orders and set big value of slippage.
In this case order will be executed wit the same rules like market order.