Unfortunately the "clicks" on the micrometer sight usually aren't quite precise. Anyway, they certainly don't equal an MOA or any other measurement like that. The only way I can think of to get a precise knowledge of the value of your sight is to clamp the gun in a shooting vise, or fire it from a bench and really take your time... firing a couple of shots at a well defined target at say, 25 yards. Then, raise the sight one click. Fire a few more shots. raise one click... repeat... measure the distance between the centers of each of your groups, then add them together and divide by the total number of groups. Mulitply the resulting value by 4 to get your 1 click at 100 yards MEAN value. Obviously, you could then double or triple this value for 200 and 300 yards.
Which is not to say that this procedure will provide precise adjustments at those distances... realistically, with enough shooting you'll develop a more precise feel for the sights on your gun... But is a starting point.