I tend to use the No. 1 screen, the all matt with the ground glass circle. It's the one for the ProS with the dotted vertical framing lines but no horizontal framing lines unlike the screen for the Pro. Because I use gridded screens in my Nikons, I bought a No. 2 'checker' screen (Also known as the Type A4 screen for the ProSD) as I thought it would help with my lack of ability to get horizons flat. It certainly does help, but the thick blue markings are something of a distraction, not like the pale lines in the Nikon 35mm equivalent. I also have a Type D cross hair screen (also known as a number 5) which is used for parallax focussing in macro, which is something I do a lot of. I got it really cheap as a clearance item. The central area does help, and parallax focussing does work, but for some reason the rest of the screen is really dark and falls off in brighness to the edges, so it not very good for composition.