Long story. I had been using .530 Hornady swaged balls, and ran out. So I switched to the Hornady box that was in my bench bag, and didn't look at it closely. They are .535, and with a .014 patch, pretty tight. Matter of fact, I had to pound them in. Anyway, once I got that ironed out, the thing with the glasses came up.
So I was shooting, and the glasses were forgotten, and this is what I came up with. But, alas, I only read the top post of yours with the rules, and rested my elbows on my knees. Then when I got home, I saw the new or adjusted rules. I still like the target though.
Had my eyes checked today, and the doc says my astigmatism in my shooting eye has changed, and that's the cause of the glasses problem.