Questions about options and LEAPS

I'm pondering whether I should long some of my RIMM via options (or LEAPS). My experience with derivatives is limited.

So, here is a question to everyone: How should I size my position? And more importantly, how much out of money, and at what expiry date? I'm interested in using it as a risk control. I'm interested in the principles and reasoning.

Thanks.

(Disclosure: Long RIMM)