[Kavious]

Theres a pet guide: https://wiki.project1999.com/Pet_Guide

In order to receive full experience for a kill solo, you need to do more than 50% of the damage to the mob. If your pet out-damages you, it will take 50% of the experience away from the kill. This is a major change from the previous system, in which you only needed to do a single point of damage to the mob in order to get full experience. If you are grouped, you and your group will get full experience from the kill, regardless of how much damage the pet does.

Though Im not familiar offhand how much xp would be lowered in a duo per kill. I would think its far more efficient to duo