I know it’s been a while but I figured I would update this in case someone else needed the info:

you'll have to give up one of the LS functions in order to free up a LS output. MIL is probably a good choice. LS stands for lowside which means a ground output whereas a HS is a highside which is a +12v output. So to trigger a relay with a LS output, you would connect one leg of the relay's coil to switched 12v and the other leg to the LS pin. When the LS pin activates, current will flow through the relay coil causing it to pull the contactor switch closed thereby turning on your fuel pump.

For the LS table configuration, setup it up as a General Purpose output. This is just a guess but you might want to turn on this second fuel pump right before going into boost so you would setup the tables to reference at least MAP and possibly engine speed like this:



This way, when MAP hits 90 kpa, the LS output will turn on and the secondary fuel pump will activate right as you're going into positive manifold pressure and need that extra fuel supply. Leave your primary fuel pump configured the way it is and then adjust the activation point of the second pump to suit your needs.

 

Good info here. Thanks for taking the time to explain.