1.5 hours on a good day you can train a pet, a bit more for a weak 1-5 pet(getting that 1st level can be a trial). Mages, burning and Crazy, energy vortex's (3) use one up move to the next, most dino's, Narvey, wind elemental and other creatures in that dungeon work as well.
Use two pets for your 1-5 pets one to tank for your trainee, a 3 or 4 level Cu works well for this.
You only need to level it one time and adjust its resists and hp and you can lose the tank for the rest of the training.
Now that's just leveling not skill training, skill training can be a pain but there are ways to speed those up too.