You are considering two very fine breeds. Are you aware of the cost of finished dogs? They will probably start at $2500.00, and go up from there, maybe a little less?
Finished dogs from field trial stock will be familiar with horses! And started dogs from the same!
Good luck in your search, and hope you enjoy many days afield with the dog you choose!
P.S. don't overlook Vizslas, they are very fine huntings dogs, very similar to the GSP, just smaller!