It really depends a lot on your eyes and how they focus. I have guys that have me order them sights with .039 and they do great. I personally prefer .019. It's a size that works for me. I tried the .010 on my 50 and 60 yard pins a couple of years ago. They were just too little for my eyes to focus on properly. Try them all if you can and then use what works for you and your eyes not what works for your buddy

Dan