Terra,
Nobody knows more about raising trophy trout in small ponds than our friend Cecil. He has raised some monster trout. If he suggests browns, I'd go with browns.
This is Cecil and one of his back yard browns:
I don't have a lot experience with browns, but if they feed anywhere near like rainbow, they will grow quite fast. You just have to make sure you supply a good high protein feed, and not so much as to degrade water quality, but enough that they grow really fast.
With the description of your water source, I think you could go near the high end for quantity. At least out here, trout are relatively inexpensive and easy to locate from dealers. It may be worth a try with a small quantity. Keep increasing the quantity to see when you reach water quality limits or die off.
Good luck. Keep us informed.
Ken
