Of course there are limitations, but the rule remains the same--less gpp is where you will get more speed, all else being equal.
I do use the same bows for 3-D that I use for hunting, as most folks I know do.
Shot distance can vary a lot--I'm at the TBOF state championship right now, and the shots today were anywhere from under 15 yds to 50+ yds--and the closest shot on the range was the toughest one IMO because it was a very tight shot between two logs.