Good advice.
The density and overall width of your pattern will change from shell to shell and choke to choke. Finding the best combination is the search and the fun! The location of the center mass of your shot should not change much from right to left and up and down. This is the human element. A shooting rest of some sort will eliminate the people issue. I have one of these
https://www.cabelas.com/product/shoo...7.uts?slotId=2 It's not very expensive but does the job.
Some form of dependable sights is a good idea. I have used the tape on style with reasonable success. I agree the magnet ones are a bad idea.