Mike:

Scope lenses aren't really measured in powers, they use these numbers to appeal to those of us more familiar with rifle scopes. The proper way to measure a lens is in diopter. The power changes depending on distance from your eye, the only constant is the diopter. To get a true 4x lens, look at the following chart and it will let you know what diopter lens you need to get a true 4x at the distance from the lens to your eye.

Also peep diameter will greatly affect clarity of a lens, just as much as a clarifier lens. I know a LOT of pro's that refuse to use a clarifier lens because they can distort an image if it doesn't come back the same way every time.

The below link will show you what diopter you need to get a true 4x for your setup.

http://www.sureloc.com/faq/diopters.pdf

Hope this helps, and hope you slay some X's with that A7. Sorry I haven't shipped the other string yet, will try to get on top of that this next week.