Any secret process to setting the scope reticles perfectly verticle/horizontal?
Every time I shoulder the rifle to check, the crosshairs seem to be just left or right oof perfectly up & down!

Not really a secret but its pretty easy way to do it. Set scope on lowest power, mounted on rifle but loose enough in rings to turn with some resistance. Stand in front of a mirror and look thru scope at the scope/bore in the mirror. The cross hair in the mirror should bissect the bore of the rifle. If it does the scope is perpendicular to the bore which essentially means it is level with the gun as it is assembled.
Tighten rings by alternating front to back side to side and finally torque ring halves to 12-15 in lb.
There are dozens of other methods but this one is the fastest, easiest and most repeatable method I have ever found.

I'll try it right now!

OOPS! This scope goes down to 6! Pretty blurry in the mirror.

Set a level on a flat part of the gun, then a level on the top turret. Adjust to match.

put a level 30 feet away. make sure its level....
set gun up level with some sand bags or sumthin...
look through the scope and adjust to the level 30 feet away.make it where you can see the bubble. i can usually see the difference in the scope if the bubble is leanin one way or the other and adjust to be more exact. i dont have any flat spots on my rifle to level it that way. so i just eyeball as best as i can.
i am likein the mirror idea though and will try that some day.

http://www.youtube.com/v/rIjQz6nahrw&hl=en_US&fs=1&

I think everyone pretty much nailed it with some good ideas. I use levels like in the video because I have some that I use on my bow.

Levels plus sight vertical crosshair along a known vertical line (like a distant door jamb that has been checked for level first).

And they're only $20.00!!! Puts the cross hairs directly level to the shooting platform (theoretically).

Those wheeler scope levelers are a waste of money. You can get 2 little levels for 1 or 2 bucks apiece at wal mart or a hardware store.