How many EA licenses can be sold before slippage is introduced

Good day all!

I have developed an EA that does very well as a scalper. I know that if I choose to sell it or give it away, the more people that trade it will eventually introduce slippage into the market. Especially if they are all trading on the same broker. Does anyone have any experience with how many copies can be run on a single broker before the amount of slippage begin to affect the effectiveness of the EA?

Test results posted here on Demo account

http://www.myfxbook.com/members/ibth...ckmill/1287479

It does not do anyone any good to make an EA available if by doing so will limit its effectiveness.