$60/slot from someone that is likely making 5-10X that an hour in their day job via base salary (not including stock grants) is a bit ludicrous. I like the idea, but you really have to charge what the time of these people is worth. On one side, this pricing will likely only serve to further the interest in the product from a customer. On the other side, you may actually get real significant talent onto the platform, not people who are trying to run a consulting business.
How about this - pay the expert a portion of the salary. The $/hour would make a bit more sense, and the 'experts' aren't going to laugh at how overrated the recruiter is in the process.