I am an older shooter (almost 68) and I shoot 12 moa dots on my c more railway red dots. I like the larger dot as I feel (for me) it helps in target acquisition. I shoot a Tac sol x ring rifle in RFPO. I use the c mores on all of my steel pistols also. I like the Striplin 90 degree mount for the pistols as it gets the dot closer to the barrel. I think I read somewhere that c more is going to (or already has) make a 10 moa dot - this might be a good choice. Good luck George
I would recommend a minimum of 6 MOA. Larger is probably going to be even better. Most prefer the largest dot sizes available in the platform they are using. I am using a 30mm MatchDot II with the 8 MOA Dot Size selected. That is the largest Dot Size I can select with this sight. I set the brightness as high as I can without the Dot Blooming.
I use C-More Railways on my pistols and for action shooting and Steel Challenge I choose a 12 minute dot. The larger the better. You are not looking for pin point accuracy just minute of plate and those targets are big.
I use a Delta Point Pro with the triangle on my RFRO gun. I use a c-more RTS-2 on my Volquartsen pistol with the 6 MOA dot. I wish it was an 8 MOA though. I use a 12MOA on my STI Steel Master for USPSA competition.Th bigger dots and triangle are easier to pick up and don't get washed out in the bright sun. Your not shooting bullseye you just want to hit the target and move fast to the next target.
just a comment, not on dot size, but the format of the viewing screen... I have the large 510c Holosuns on both my 22/45 MKiv and rifle... allows me to transition better than the smaller Venom I was using...
disclaimer: I'm just a mediocre B class RFRO shooter, and as I've commented use a 510c.. when I shot practical pistol fairly seriously for 25 or so years, I worked a lot on the mental game.... I visualize the small 2moa but bright dot subconsciously when the shot breaks, and can interpret pretty quickly whether a hit or not...especially if near the edge of the plate.. as I've commented, the large viewing window is an asset to me.. regards