
Is have GSP and my dogs are worked and shown at championship and international level.. All are docked. There are very few shows that you cannot attend with a docked puppy so from a showing perspective having a docked tail is no disadvantage. Our top dogs are docked year after year.
As many of the established breeders of GSP aim for duality the vast majority seem to dock, now there are a few notable exceptions so if you want an undocked puppy from established breeders with proven track record you will have a narrower range of breeders to approach.
Personally I would not work an undocked GSP so if you plan to try your hand at gundog training I would recommend a docked dog. I recommend all new owners attend basic gundog training even if there is no plans to continue long term. By attending training with people who understand HPR breeds you will learn how to read your dog when it is off lead, it WILL be hunting even if you are just planning a walk. By training with knowledgable trainers you will learn to read when your dog is on scent and recall or stop the dog before it gets trouble.
I would also recommend attending a few shows to meet breeders and see which dogs actually take your eye to help focus you to a kennel or breeder who would like to buy a puppy from. Please feel free to contact me for a chat if you like.