What is the average window period for the herpes igg antibody test? what would the likelihood be of being positive when someone tests negative for both 1 types 17 weeks after possible exposure?

No chance: With negative results at 17 weeks, you can be sure you weren't infected. Even if you happen to be among the rare persons who don't develop positive blood test results, if negative at 17 weeks, it won't turn positive later. If you have had no symptoms typical for a new HSV infection, that fact plus the negative test makes it virtually 100% certain you were not infected. So no worries. Best wishes.

Unlikely: If you have tested negative 1 and 17 weeks after exposure (IgM and IgG), then consider yourself negative