I've installed and used several pistols with the Novak Ghost Ring rear sights.
My 4513TSW has a Novak Ghost Ring with a single tritium capsule located at the bottom, and it works well with the front tritium sight post in low light situations.
Until recently I had similar Novak Ghost Ring rear sights on my 3913 & CS9 ... sans tritium capsules ... but I finally decided to replace them with standard 2-dot Novak style rear sights.
While the Ghost Ring rear sights were very fast and easy to use for reasonable 'close range" shooting ... which for ME means 3-11 yards ... they slowed me down once I moved past the 11 yard line. Of course, even Novak will state that this sight isn't intended for anything other than close range application. It's just that these 2 pistols are so much more accurate than the Ghost Ring rear sights allow for, that I decided to change back to the regular 2-dot rear sights ... except with tritium capsules in one case.
I had the Ghost Ring sight on my 3913 for more than 3 years, and I've used it quite a lot. It's very fast and easy to use at 3-7 yards ... against large, full size silhouette targets. Period. It allows the eye to "center" the highly visible front post, and "funnels" the eye toward the front post as the post covers the intended target.
It DOES, however, fade out to near invisibility under diminished light conditions, such as trying to acquire a full aligned sight picture in the variable shadows of our outdoor range, even with the Mercury Vapor lights turned on and located above & behind me ...
Also, trying to use the Ghost ring for "precise" aimed fire, such as shooting the little wooden clothespins off the cardboard target boards, becomes difficult because of the wide, shallow "dish" shaped rear sight. I can use it for 50+ yard shooting at pepper poppers, but it's harder than when using standard sights.
I'll be switching out my Ghost Ring on my 3913 this weekend, replacing it with the standard factory (Trijicon) rear sight ... and I've already replaced the Ghost Ring on my CS9 with the stock 2-dot Novak style steel sight.
I also have an older Ashley A/O BIG DOT sight set on my CS45. Mine is from when the rear sight base wasn't offered with a tritium capsule in the CS45. The front sight is VERY easily seen, even as it's rising up into your peripheral vision. I like the easy-to-clean and SEE white plastic ring of the BIG DOT front sight post, compared to the lightly painted white outlines around the regular tritium sights.
The BIG DOT set up takes some accomodation and adjustment, though, on the part of the shooter ... as it aligns a bit differently than the now-standard 3-dot sight set ups. It's also not really "recommended" for other than "reasonably close range" defensive distances, as well ...
For "older eyes" ... I'm 50 ... the BIG DOT sights are RIGHT OUT THERE, right in front of you ... compared to the somewhat fuzzy and "less distinct" white dots & white outlines of other sights, both front & rear. I've had to re-apply the white paint to my regular painted "dot" sights, as well as around my tritium capsule-equipped sights, but this must be done carefully to avoid leaving any paint residue over the capsule cap/lense. Plain black sights and plain stainless steel sights are more difficult to see for my older eyes under some circumstances, it seems ...
If my 4513TSW rear Ghost Ring sight lacked the lower tritium capsule & dot I'd probably replace it with the Millet adjustable rear sight I had on it for a brief while. On the other hand, if the Millet rear sight hadn't been plain black, but I'd instead ordered it with tritium capsules ... then that's what would be on the pistol as I write this ...