I used a Mildots quite a while back when I first started getting serious about long range deer hunting in Alberta where the shots were long field shots and the white tails were big bodied. It worked out quite well as the average size from top of the back to the bottom of the chest ran a pretty consistent 18". As previously mentioned, measuring to the ground is difficult due to grass, etc. it worked out well since one mil was the chest measurement at 500 yards. I didnt need a chart because the range adjustments using the Mildots could easily be memorized. If I thought the deer looked smaller, or I was after larger mule deer I would add or subtract 50 yards from my basic measurements taken using a 18" chest area. I was able to get range measurements out to 600 yards that ran +/- 40 yards between 400-600 yards. My range error was reduced substantially when I switched from my 308 to a flatter shooting 270WSM with high BC, high velocity loads. My max measurement range using Mildots on coyotes with a 9" chest would get me to 300 yards. The larger the target, the more precision. Also, for me, I found that the tactical milling reticule design with the finer reticle divisions could further improve ranging accuracy over the Mildot format. When I got a decent range finder, I used Mildots only as a back up RF conditions were poor or shots were at shorter ranges.