Ben, I came late into this. A 120 lb. male dog would be a very big dog. I have dogs with really good bone and my males rarely go over 100 lbs and they stand 26-27 inches in height. Please take note of the standard sizes for dogs and bitches. You will see a lot of oversized dogs being shown. We do have a standard but many people choose to ignore it. My first RR was a spayed female and she was 125 lbs when she died. She was huge, extremely lazy, adored food, and looked like a beached whale a lot of the time. I don't think her overweight was the cause of her death, but it might have had some really bad effects if she had lived to old age. A good rule of thumb if you haven't got a scale is that you should always see the shadow of the ribs; note shadow and not actually count the ribs which would mean the dog was too thin, but it is better to err on the thin side than to let them get fat, which is very easy.
Since you are only looking for a pet, I would suggest that you spend some time with the litter and let the puppy pick you. You want something that will be your companion and bond with you. Your breeder should be able to tell you the character of the individual puppies, but the important thing is that they and you bond. We picked our Dobie pup many years ago simply because she grabbed my husband's shoelace and wouldn't let go. We had her for 12 years and she was a wonderful pet.
Health of the parents would be the single most important thing. At a very minimum both parents should be X-rayed and the hips and elbows cleared with a minimum of Good on the hips. You then might want to ask about Thyroid testing, and after that whether parents' eyes had been checked. Then insist on the breeder having your puppy examined by a veterinarian 24 hours before you pick him/her up. In the contract it should state that you then should take the puppy to your veterinarian within a period of about three days after taking delivery to establish a schedule of vaccination and to check that in fact you have taken delivery of a healthy puppy. Doing this safeguards first the breeder and secondly you.
If you live outside the United States, it is possible you will not be offered a contract as in many countries a sale is sealed with a handshake, but in the US it is important to get a contract from your breeder who should also give you a "puppy packet" with lots of information about the care and upbringing of your puppy. RRCUS now actually supplies breeders with a puppy packet, but your breeder may already have put together one of her own.
Please feel free to ask this list any questions you need to have answered. You will find a lot of first time RR owners on the list who have probably been through many of the same experiences you will be going through.
Caroline
