I will say to you what I say to those looking for technical co-founders: Learn to do it yourself first, until then, you trying to evaluate them is like a deaf/blind person being a judge on American Idol.
Think about it, a deaf/blind dude reading up on how to evaluate good music/dance. Or flip the problem, do you think a business guy, pure and pure, can read some stuff and then be able to judge which one of the guys on your team is the best hacker?
I know the skill set is different, but the concept is universal: you have to know a craft in order to appreciate it in order to know/tell the difference.