i have owened GSPs for 30 years and here is my .02. There are two distinct breed variations of the breed. The dark heavy boned (DHB) and the mostly white lighter boned (WLB). I have owened both. The DHBs would hunt at a modest trot all day every day normally from 30-60 yards in front of you. The WLBs were bred for field trials and they would cover large tracks of land.
I haven't owned GSPs for 30 years, but had several from the Mid-Sixties until Ziggy died in 1983. Since then I have owned GWPs. While you may feel there are two distinct variations of the breed, I assume both variations, like Drahthaars and GWPs are genetically indistinguishable. My experience with the two variations you speak of are totally different than yours. Back in the sixties and seventies, the long legged, big boned, deep chested individuals with the large square head were generally registered FDSB and were the field trialers. Back then there was no NAVHDA for the Continental Breeds. If you wanted to compete and get titles you had to run your Shorthairs with the setters. Since Shorthairs primarily use ground scent with their heads to the ground when looking for birds as compared to the heads up high Setters that use airborn scent, they were slower and thus a disadvantage for timed trials. Breeders thought that by breeding long winded, long legged individuals, that not only would they be faster on the move, but they thought by getting the head up farther from the ground the dogs may switch to airborn. They also bred them for large box shaped noses for more olfactory cells and more air intake. The dogs never did bring their heads up, and the breeders ended up with large dogs that could work all day at a Shorthair pace. While they still were slower than the setters, they would out work them in the field on a all day hunt, cause they would tire. The smaller, more petite individuals were basically bred for show and AKC registered. They were smaller and finer boned so they fit in kennels and traveled well. They did not need the long legs nor did they need the huge box shaped heads for smell in the show arena, but the lack of them was a distinct disadvantage in the field. To this day, I hate the look of a pointed nose on some Shorthairs. I never did see a color preference to either as some my large boned hunters were mostly white with very little ticking, while others were heavily ticked. In the early seventies, test and trials for "versatile" type hunting dogs came to be in America(had been for years in Germany and Canada) and the GSPs, GWPs and other Continental breeds had a competition of their own. As evidence of how new the Continental Breeds are to the U.S., in the 1972 remake of "The Biscuit Eater" the film makers used a GWP as the "Feral" dog turned bird dog.......because it looked like a mutt and not many folks even knew the breed existed.