I've been "practicing" for 20 years with my TX's. I am at the point that I know when I made a good shot and when I didn't. I was recently on here moaning about my bad pellets, until I figured out my scope needed some changes. I had left it, as is, for the last 10-15 years and my eyesight had changed a good bit. I still don't know exactly what I did, but all is much better. I pulled one of my old 2000 model MarkIII's out of mothballs and it seems very good with these pellets. When I set up for click charts, I just zero at 27 yards. I then move in to 12 yards and write down the clicks it takes(29) and then out to 55 yards where I need 52 clicks, at present. The 55 yard groups aren't really tight, but I get a good idea where I need to be. I get many groups that are less than an inch and all around my 55 yard poa, so that's good enough. I then look for an old click sheet, I have very many, that have numbers that match my 12 and 55 yard real world numbers. I even know about what velocity I'm shooting by the 1/8th min. clicks needed for the 55 yard shot. I'm right on 800, with Exacts 8.44, but I don't have a limit like you.