3 accounts is enough. When the commission is embedded in the spread, you don't know how much you are paying. On USD/JPY one mini lot is $1 ($1 = 1 pip on a mini)

Also with FXCM, their quote is always a pip or 2 or 3 lower than EFX Guess that this makes it possible for them to buy or sell below market and cover above. Now that's a money maker and certainly lowers risk for them.

On a normal day, which today is not, you can watch the spread actually go to zero. I have even seen it cross to the bid higher than the ask. But that only last for the blink of an eye.