You don't have to park a toon at Bert if you don't want to. Once you've done Gnomergan, the mana servant in both Broken Isles Dalaran pet shop and in your faction capital for BfA will teleport any 120 to Gnomergan. Step around the corner and fight Bert instead.
You can park your spare toon at either Gargra in Frostfire, or Vesharr in Arak, both of whom will take a level 1 to 10 without buffs, and to 17 on battle weeks.
Ugh--I am doing battle during pet bonus week and am not getting extra experience. Am I doing something wrong. Two pets are 25 and the other is for leveling. I am wearing safari hat and using two treats. :(
I have alts parked at Crysa, Bert and Ashlei, log on daily and do 3 fights. Andurs when up Ill treat up and go for an hour. Would be interesting to see which fights, like Bert, have random pet drops. I have had 6 dibblers and levelled a brand new hunter from 1-11 just with Bert.