Forex spreads and commissions

Hi there. I couldn’t find any info about spreads or comission for forex trading. There is a bunch of topics dating years back (up to 2005) but even they don’t provide any info.
What spreads\comissions are used by C2? Is there a list, like brokers usually have?
I understand that C2 tries to be a multibroker system and these values differ from broker to broker but there should be certain standard values that are used for estimation of strategies efficiency.

Thank you!