For my birthday, my wife bought a new Nikon Bushmaster 4.5-14-40. My old Conetrol 2-pc bases and rings puts the scope too close to my eye, 12-1/8" from the recoil pad. It was hittin me between the eyes. I couldn't move the scope further forward.
http://i26.photobucket.com/albums/c129/GSSP/Nikon4.jpg

I've purchased a Ken Farrell alum picatinny base and some Tactical Systems medium alum rings.
http://i26.photobucket.com/albums/c129/GSSP/Rightside4.jpg

Not sure how far I should set the scope from my eye.
http://i26.photobucket.com/albums/c129/GSSP/Closeeyerelief.jpg

I forgot, the scope is 4" from my right eye. My 16 yr old daughter took the pic and made the measurement.

I adjust scopes for eye relief by loosening the ring screws and sliding the scope back and forth until I have the optimum view through the scope.There is always a bit of compromise between a sitting/prone position and an offhand position, but most scopes today have a degree of non-critical eye relief that allows you some “wiggle†room.

Your rings should always be placed as close as possible to the junction of the tube body and the objective and ocular bells, but since you have the Picatinny rail you can also move the scope/rings fore and aft on the base as a unit if you have to.