I guess most overlords don't want to give away their strategies.
Truth be told, there really isn't much strategy involved. Reinforce is hands down the best Level 3 OL card in the game. As far as I am aware, getting Reinforce as quickly as possible followed by Web Trap is the way to go.
In another thread it was suggested that OL cards are purchased on a per-quest basis. I am a big fan of this idea. We've made it a house rule and had great success with it so far.