Are you going to the Rose City Labrador Retriever Club show at Champoeg state park July 12th, 13th and 14th? I would normally be attending this show, but I have 3 week old puppies right now. This will be an excellent opportunity to meet breeders and look at their Labradors they are exhibiting.
If you go, please feel free to talk to breeders about potential litters they have planned, but be watchful of whether they are about to enter the show ring or not, as that can be a stressful time. If you see someone grooming their dog, playing with young dogs, or sitting at their set up, strike up a conversation with them, and tell them you are looking for a well bred, nice companion dog to add to your family. I know most breeders there would be happy to steer you to a nice litter, or answer any questions you may have. I wish I were going so I could meet you there.
The CHIC (Canine Health Information Center) health clearance recommendations are a good place to start, but I would make an echocardiogram, as well as the Prcd-PRA exam to the list mandatory.
Canine Health Information Center: CHIC Information
If you have any questions about the tests, please ask and we can explain them.