RE: Low or Medium
eldeguello has given you good advice about the stock and the comb. However I have found the comb's to be too low on most MZ's, and for most shooter's. The best thing you can do is to mount the scope properly(as close to the barrel as possible), and in proper alignment. Then do what you need to do to the comb to make it fit you. Normally a raised comb device is needed. This can be anything from moleskin to a leather cheek piece-depending on the height needed. If you make the gun fit you properly like I said, or if you make the scope fit you like eldeguello said, then you will shoot better.
Most MZ mfrs. make their comb too low, because it is easy to raise your ckeek slightly. But if they make them too high it is very difficult to lower your cheek. Tom.