So my Slim adjustable arrived in the mail this afternoon. I cant wait to shave with it tomorrow morning. This will be my first razor besides my Merkur 34C that I have used. I have been DE shaving for right at about 3 years and with my 34C if I am just trying to go quickly I can get a DFS in about 10-15 minutes with my feather or personna med prep blades. What number should I set the Slim at to start?