These are very popular stones. 8" Dia-Sharps have a single grit per stone making them more expensive, but at 8" by 3" they are wider than the 8" DuoSharps, offering a good working surface. The 8" Dia-Sharp line also has the widest range of grits available from DMT, with extra extra coarse, medium extra fine and extra extra fine options not available in other sizes, so it is good line to consider. One coarse and one fine stone is a good starting point.
Today, however, there is a whole new generation of mechanical sharpeners that are far more forgiving for those who may not use perfect technique. At the same time many more people have become accustomed to sharpening their knives this way and the average novice of 10 years ago is now the seasoned pro. It is still possible to damage knives with an electric sharpener, but you would have to either be trying to damage the knife or have some type of accident in order to do so.
You need the right size of sharpening stone that fit the type and size of your blades and tools. In general, 6-inches stones are the smaller models and 8-inches are the larger ones. The stones larger than 8 inches are work best for big-sized blades and tools. You may also find sort of ‘pocket knife sharpener’ out there. Most of the credit card sized sharpening stone are smaller than 6 inches and ideal for on the go sharpening not for regular basis.
Removing the burr is fairly simple. You'll need a leather strop or block (this sort of thing), which is designed to catch the metal fibres from the knife. You could do it with a fibrous tea towel or some newspaper if you like, but I'd suggest going with leather to begin with. The motion is fairly similar to sharpening. Draw the knife over the leather, going away from the edge at roughly the same angle as when you sharpened.