I'm just a relative new comer, training with my first real retriever.....but I ike the 2" dummies for most everything - they're cheaper and I can carry more. (I have a doz of the white Avery hexabumpers) - Many people like the Neuman & Bennett's, also. I do have a couple of 3" bumpers that I use when i need to throw farther or have mouth issues (ie cigarring) that I'm working on. For variety, I also use some Dokken DFT dummies. Given one choice, I'd say use the 2x12" kind.