In my opinion, you may want to drop the price tag on entry. It is widely looked down upon (eg — pay to pitch, etc) and will make you lose some credibility when it comes to discovering serious talent.

Also I feel bringing religion into business (which is essentially what startups are) is unwarranted. Don't get me wrong, but there is literally no correlation here.

You seem like a genuinely nice guy so I just dropped in my 2 cents, and yes, you should reach out to Slack. Best of luck, mate!