This is worth posting.
It's a schematic of the FW-190. Look carefully.....
Make a note of....
a) the center-line.
b) the sight-line.
c) the position of the reticle
d) the horizontal separation between centre-line and sight-line - 40mm.
Now grab a tape measure, find a mirror and measure the distance from the centre of your nose to the middle of your right pupil.....
Mine is 37mm.
The offset Revi gunsight is installed to sit directly in the right eye's line of sight.
No leaning required.
Here's a link to the full image....I'd post it here but it's a bit big....3mb.
http://www.mediafire.com/imageview.p...n77up7&thumb=4