How in-depth should buyer profile be in first contact with broker?

As several of the previous posters mentioned, it should be whatever you feel most comfortable with providing. In my experience, the broker / advisor is screening to make sure you have the financial wherewithal and/or can quality for financing to acquire the company prior to investing time talking with you about this opportunity.

While I appreciate the need for brokers to vet a buyer's ability to afford a business and get a deal done, we have a local group that I think takes it too far. If your net worth is anywhere south of the asking price, they say you can't afford it and you're cut off. It's as if they've never heard of raising capital or getting an SBA loan. They have a pretty bad reputation among searchers in town, though they must have a number of multi-millionaire friends in their rolodex. I understand their job isn't to make friends with searchers, but they just cut you out of the market completely if you don't have enough zeros.