You should be fine with a few exceptions. In a bed room I have a 1K 400W, 3 fans and washer on the same breaker and about the same on the other. The only thing, with a 600 in a closet you will kill your plants without proper ventilation. IMO you will need at least 200 of CFM to pull the hot air out of the closet, and for my self I would use more than that. I have done a cabinet grow with a 1K in it, so have plenty of experience with growing in small spaces withat venture along with some other cabinet veging along with my current veg closet with a 400W with air cooled hood.
Adieu