One of the guys over at Specialty Pistols website is getting the VHR reticle in the 6.5-20X also, and i think i've convinced him to measure the reticle also at 20X. It's supposed to be inversely proportional, but that's assuming the power ring is relatively accurate regarding magnification. I used to play around with calculating a particular subtension for a particular scope right out the front window of my house using measured signs at a lasered distance from my window. Most of the time most of the scopes were very close to calculated. I was also able to measure reticles along a sign post 98 yds. from the window (most sign posts have holes drilled in them at exactly 1" on centers). I've found the Thompson Targets with the red squares that r further didvided into .25 inch per hundred yd. provide the easiest method of measuring tho. Here's a link that should give u the most exact system of measuring (as far as i can tell). This copied from opticstalk.com--
http://opticstalk.com/forum_posts.asp?TID=8223
I still can't believe that Leupold didn't calibrate the reticle subtensions for the highest power though on that scope--crazy.
If u wish to adjust power (subtension) for the best trajectory fit (even ydgs.) here's something copied from SP site again that should be the simplest method of doing it (non-calculated)--
1) Establish the load u want to shoot, and record MV.
2) Run a ballistics program and manipulate the x-hair zero until u get the best (intuitive) trajectory to reticle fit possible. What this does is it simply establishes your best x-hair zero for that reticle.
3) Set tgts. at each distance that the stadia r supposed to be zeroed at according to the ballistics program.
4) Shoot the tgts. using only the main x-hair for a zero. U'll need some big tgts. as range increases (sometimes aiming at the top of them is a handy way to go).
5) Measure the distance between the x-hair bull on each tgt. and the group.
6) Convert that measurement to inch per hundred yds. Ex-- 35" low at 500 yds. would be 7 inch per hundred yds.
7) Go back to 100 yds. and put a black mk. on the tgt. for each range below the main x-hair bull. Ex-- put 1 at 7 inches below the bull for the 500 yd. reference.
8) Go back to the bench and adjust the power so it best matches the actual zeros, paying particular attention to the longer ranges as error at LR has a larger effect than short range.
9) Mark the scope somehow (might write it down too somewhere).
10) Now remeasure your windage stadia, and relaculate the windage system.
Now when out hunting all u'll need to think about is making sure u adjust the power correctly, and windage if it exists, since vertical compensation will be intuitive...once practiced.