If you are using Boost for Remote, use "BN" port for maximum power.
If you aren't using Boost for Remote, use "OUT1" port. OUT1 port has half the power output of Boost BN port.
If you are using Contact you can use "Colloidal Silver" port on Boost v2.0 or the "High PWR Contact" output on Boost v3.0.
Note Port and Output (connector) refer to the same thing.
For more details, please check the link: