Hi I want to buy a clipper of my own to do Ollie properly. At the moment, I have a rubbish clipper, although it does the job, I want a new one that does the job better. I'm thinking of getting an Andis Single Speed clipper, with a 7F blade. Can I ask if the 7F blade is correct for clipping a cocker spaniel? (he's done short on back, front of legs and head).