I am trying to buy covers for my scope. The objective is 2.230 and the eye piece 1.715. Butler Creek has 30390 #39 at 2.220 and 30400 #40 at 2.250. eyepeice is 20180 #18 is 1.700 and 20190 #19 is 1.730. Should I go up or down? Anybody know the size USO recommends? I know the difference is...
