I think this is sensible, and a good analogy. Once you've done a few startups, you'll realize that choosing a partner, or partners, could easily make or break you. Partnerships are easy to get into, the good ones are easy to get out of, the bad ones are impossible to shake off.
From your post, it sounds like you're worried about getting this guy "in" with you. If you've got the idea, and are driving it, you offer something very few people do, don't give it up on the first date! You might hate this guy, or he might hate you. OR, he might want something you can't offer.
I'm still learning about this myself, but have in the last year or two begun to strongly prefer trial-period type situations, ones that could last a while. We recently invited to people to join our board, and they are on one-year probationary terms. They were happy to join on those terms because they want to help.
I'm happy to try them out, without worrying about giving them equity now that might be the wrong amount later.
I could say a lot more about this, but I think overall to find a partner in the very early stage, you should generally: pitch the IDEA and business hard, be cagey about promising equity participation, and make CERTAIN that the person will be able to contribute by asking them to contribute for free, or cheap first.
