We seem to be on the same "track", I am also returning to HO after decades away.
We both have a 5 x 9 area. Mine was first created back in the 90's with my sons. When they left the layout went up in the barn rafters for about 15 years. After retiring I decided to redo it last year.'
See drawing in (Ed S stuff). I do not have any reverses in my 5x9, but another drawing shows where I will be adding a little more track. The new section will have a reverse loop, a wye and a double cross over between 2 main tracks. So I have reverses to deal with.
From reading an experimenting I have decided to reverse protect whole districts.
I started layout in the program RTS 8.0 which shows wiring conflicts and resolved those. Now I am using XTrkCAd 4.03a so I can work on clearances.
Looking at your lay out I see the reverse loop in the middle. I would put a reverse protector to the left of switch 7 and protect that whole district. Then gap all the track leading into that district.
If your are using RTS 8 you can send me the file and I can try it out and I can send you mine if your are interested.