My brittany gets cut a lot since she spend half the year training and on the trial circuit. Seems to me everyone I know uses a #10 blade going with the hair. Heck, I even shave my lab during the summer with it. It seems a #10 with the hair or a #5 against the hair is about the same cut. Don't use a #10 against the hair, you will have a bald dog. I did a lot of research and it seems most people I talked to use Andis shavers. They are expensive, but pay for themselves with about 4 trims. If I did it again Id get the high speed 3400-4300 RPM version. Mine are the 2700-3400 RPM version and Ive never used the lower RPM. The high speed would be nice cutting through my labs undercoat.