RE: which breed of dog?
GSP or Lab,
I own three labs and use them for pheasant. They are disciplined, smart and very loving to people ( currently rank second to Newfoundlands as best w/ kids). However, the key I have found to getting a "upland lab" is body type. A lean, long legged lab can cover more land and is less likely to fatigue than the traditional stocky- shorter legged lab afield. Sounds a lot like a GSP.
Not a fan of spaniels, particulary for pheasants. In my South Dakota group there is a guy with a spaniel. He spends a great deal of time working burs out every night after the hunt. One year he had to shave areas of hair off the dog.
I have also been bitten by two of them when I was gently petting them.
-MC2