There is no difference in the number of wands earned by premium vs. freemium characters. They both get 50 wands each time they capture/enchant. The difference is in how much mana they remove/instill (1 for premium, 1/2 for freemium).
Right now, there are only 5 characters who can fight the monsters, so the maximum number of wands is 250 per 4h round.
I think the number 600 is coming from daily tasks. Most of them award 200 wands, but apparently there are some that award 600 (although I have yet to see one :'( ).