Re: how much is too much?
I've posted this before, but perhaps it can be instructive again:
Place a target @ 1000 yds, and look at it through a scope set at various powers.
It will appear the same as viewed with your naked eye at:
10X - 100 yds
12x - 83 yds
15x - 67 yds
16x - 63 yds
18x - 56 yds
20x - 50 yds
22x - 45 yds
24x - 42 yds
25x - 40 yds
So if that 1000 yd target was say 2 MOA in diameter (21") a shooter would have no problem identifying it, and then shooting at it with any scope, from 10x or greater. So if the target is large enough, adding more scope power does not increase the changes of a hit.
Make the target smaller than 2 MOA, or make the criteria that the smallest multi shot grouping becomes important , then scope power becomes very much a factor.
So adequate scope power is a function of size, distance and what your trying to accomplish.
Bob