Production rate with a rockhound?

[tommcintire]

I'm contemplating "sharing a rental" of a bobcat and rockhound with a fellow horse owner. I have an area of about 1/2 acre I want to pick for rocks (already harley raked it, but the rental rake was passing stones 1 inch and down, which doesn't work for my needs). My friend has an area of about 2 acres she wants to pick as well, also 1 inch stone...

Any advice on how much area you can pick per hour with a rockhound, assuming nice dry soil? It is summer in New England, and we aren't getting any rain to speak of...

-Tom