I would try and get a warm intro.

If you can't, then email is best.

Just say
- I love the app
- I've been thinking about this market for a while
- I've actually [insert credibility - past work experience, research, access to customers, etc]

Then ask if they'd like to get on a call to share notes?

Going in all excited and mentioning that you think he's not focused, etc might turn them off right away.

Build the relationship slowly, as it's too easy in today's world to archive emails and never respond.

Hope that helps. Call anytime to discuss further.