optical centering

I read a post about optically centering a scope.  Thought I would give it a try with my Barska 3-12x40.  The post was sure correct that it isn't done quickly.  Is it best to attempt this with the power set to lowest setting?  I don't know if I may be doing something wrong or what, but I worked at it for about an hour this morning and it's still not dead on when I rotate it 360 degrees.  Can anyone give me any further advise on how to bring it into center?  I'm mounting to a CFX with a beeman adjustable mount if I ever get it centered.
                                                                                                                                                         Jeffery

I'm probably a bad example when it comes to the optical centering of a scope but, I've never been able to get it perfectly centered, for whatever reason. I'm not even sure if it's a necessity to get it perfectly centered, but then again, that's just me minimizing to justify my impatience.      I've gotten scopes very close to center using that method but after about 30 to 45 minutes of playing around with it, I say the heck with it, it's close enough.  So far, I've been happy with the results, so it's really up to you.  Hope this helps.

[daved]

I have to agree with Mark, it doesn't need to be perfect, especially with an adjustable mount.  I center scopes in my shop, 40 feet from end to end, I just pick a spot on one of the doors, scope at minimum power.  After I get it as good as I think it will get, or when I run out of patience, then I jump to max power just to double check.  Remember, some scope CAN'T be perfectly centered, so close enough, is.

Dave