U-shaped outline rear sight, night sights, FO front only, FO front & rear, same colour dots, different colour dots, black only, ....
My take: NONE of those matter when shooting slow fire, to see how you group.
All those dots and lines are just visual noise. Use the top horizontal edge of the front sight post, and line it up with the top horizontal edges of the rear sight post, so the top edges are at the same height. Then, center the FSP in the RSP, so the air gaps are the same width.
Now, with your focus on the top horizontal edge of the FSP, put it where you want, and keep everything lined up as described above. Then, slowly, pull the trigger.
You will find that target choice matters. It’s hard to aim consistently if you don’t know where the middle of a giant 8” black circle is. So choose an appropriate target/aiming point based on how far away you are. Your eyes matter here too. I often use outlines of 2” circles as aiming points, at 5 yds, when helping new shooters. Plenty of white paper is a great contrast with black sights.