Well the GGS will be affected by your overall skill points used, but it really depends if you want to hunt with that tamer while they're training up. If you're happy to be taming and nothing else, then don't worry about lore. However, if you want to chill after a few hours taming and take out some pets for a small hunt, you'll need lore and vet.
I might make a younger tamer do nothing but tame for a while, but I've always soulstoned lore and vet on to another character once they got high enough to affect gains, then they're trained and available for the character if you want to hunt for a week.
Wenchy