Familiar/Summonable Ally Help
So for a game I'm going to be in shortly, I have a character who is a spirit mage, who can summon a spirit to help him. The idea I had was for it to act as a quasi-familiar, granting him a small energy reserve. Thing is, I'm confused as to how I build a familiar for GURPS, given my relative newness to the system.
The only thing I have nailed down for the Ally is Summonable and appears on a 15 or less. I have a minimum 14 points to build him on, and a maximum of 23 points I can spare for it.