I have lots of rocks and an inexpensive 6-ft rock rake. I can do a better job of spreading gravel (roadbase) with it than I can a boxblade because the rake will roll up an 8 - 10 inch wave of rocks and distribute them evenly. My rake does not have wheels on it, but that is probably a good accessory to have. Your 5210 can pull as wide a rake as you want, but it should be at least as wide as the tire tracks when tilted to the desired angle to windrow the rocks.
I also have an OLD hay rake that does a really nice rake job and the fingers are 2-3 inches between the tines. It is about 10 foot wide, but lets a lot of the small rocks slip through.
Have raked up thousands of rocks and it does a fair job. It does a lousy job of trying to separate rocks from the soil as it takes way too much soil along with the rocks and you can't shake the soil out.
The best solution seems to be one of the PTO driven dual roller rakes. They seem to cost a lot of money, but do a much better job of separating the rocks from the soil.
I believe rocks and compact tractors do not go well together (rocks are rough on equipment), so you may have a hard time getting a lot of response.
Mark does landscaping as do several others on this board and they must face this problem daily to prepare nice level seed beds for grass and other landscaping projects. Maybe they can shed some light on it. Unfortunately the developers around here just haul in 4 inches of sand and bury the rocks and hope they won't be seen until they sell the house.
If there is a reasonably priced solution, I WANT one. /w3tcompact/icons/smile.gif /w3tcompact/icons/smile.gif