I am new to the wonderful world of knives and have a question about sharpening a knife. A lot of posts praise the Spyderco Sharpmaker. I was wondering which of the three angles to use for general sharpening of blades 2-10 inches long. I read somewhere that a angle between 10 and 20 degrees is ideal but also read that you should use the 40 degree angle on the Sharpmaker to sharpen most knives. Any help would be greatly appreciated. Thanks, Bob