Hi vinnysvinyl,
Risk is based upon the account balance. You will need adjust the lot size to the amount of risk you are willing to accept for each EA such that the overall risk to the account will not cause your account to be closed out. It is recommended that you limit the account risk to 1%. With FTMO v4.3 EAs you can divide the 6 lot limit evenly between the EAs you are planning to trade. However, with the new V5 EAs you will need to set the lot sizes based upon each EAs SL.
Alan,