as far as i know there isnt a target voltage as it all looks to be based on what engine/interior accessories are being used and what load is being used by them and its all configured from there, there is a detailed post on the hptuners forum it will give u an idea of whats adjustable but remember this is all ecu not bcm so changing the ecu settings may not be liked by the bcm so it may not actually work, good read tho
https://forum.hptuners.com/showthread.php?72620-Alternator-parmeters-under-system-tab
