Despite the reassurances here by others and personal practice, I found the red dot too time consuming to acquire in the dark on my CORE. So I would not use it without adding equal height night sights to guide me to faster red dot acquisition for low (but not complete dark) light before turning light on. (Borrow one and take it into a dark room to try to find the red dot before buying or setting up yours that way.)
What you describe is not a fault of the RDS sighting system. It is a training issue with the operator. Seeing the dot consistently is the result of mastering the basics of pistol presentation. If you have to "find" or "hunt for" the dot, it is a result of improper presentations. RDS are not for everyone; there is a skill level required for them to work effectively.
Now, lest I sound too much like a complete know-it-all, I am still not as expert on presentation as I would like to be. I have thousands of dry presentations over the past year and a half, and I am probably about 90% consistent. I often practice with the RDS off, concentrating on the iron sights. If you can't do it first with irons, you won't be able to do it with a dot either. However, I know what I am trying to achieve.
In truth, the same basic skill set that produces the quick and accurate iron sight alignment that is necessary for competitive or defensive accuracy is the exact same skill set necessary for the dot to consistently appear in the window. Proper consistent grip, pistol level in front of the eyes, aimed at the target with front and rear sights aligned.
Acquiring
iron sight alignment in order to find a red dot is a training procedure. It will not be necessary after learning consistent, sight aligned presentations. If you are slow to find aligned iron sights when pointing to the target, you will likely not be able to
find the dot.
With or without a RDS, if your presentation doesn't quickly provide you with
natural iron sight alignment, that's what you need to practice. Once you can regularly present your pistol onto a target with aligned sights and then move the pistol to other targets while keeping that alignment, THEN the RDS will work for you and allow you a greater margin of error, nite or day.
Proper, consistent presentation allows you to see (not find) the dot because your pistol is pointed in correctly, even in the dark.
If you can't "find" the dot, your iron sights aren't aligned either. If your iron sights aren't aligned, you often can't see your front sight, whether a night sight in the dark or any sight in the daylight. You don't know where that front sight is--low, left, or right. It is obscured. So you have to wave the pistol around until the front sight appears, then align it. Then get on target. This is not good pistol work. If this is what you have to do to shoot, you are going to be slow in competition and further behind the curve in defensive pistol work--irons or RDS.
An RDS is not a crutch or an easy path to accuracy; it is an enhancement to good, fundamental pistol skills. A laser is a crutch. You're pointing the laser dot, not aligning your sights. The laser
will compensate for poor pistol presentation.
Once you can present properly and consistently, the iron sights truly become backup sights that you don't use unless the RDS fails. As such, three glowing tritium dots plus a red dot in dark conditions confuse the eyes (both eyes open shooting with the RDS). Maybe for training initially but ultimately unnecessary.
If one must go the nite site route, try having just the front a tritium but not the back. It is less confusing.
One of the big advantages of the RDS is that the sighting focal plane is
the target (which is natural--threat focused) with the dot superimposed on it. Adding focus on another focal plane, or two more, degrades the advantage of the RDS.
When that dot starts appearing regularly and you find yourself not looking for the irons, you will smile and say, "Ahhhhhh. I get it!" It's like riding a two wheel bike. Impossible at first, then all of a sudden everything clicks and away you go, getting better much faster.
Properly co-witnessed suppressor height sights with the windage adjustable rear closer to the shooter than the RDS and the front above the muzzle (CORE) seen through the lower part of the RDS window will get you to competent RDS use pretty quickly. Compromise on any of these requirements and you will probably remain frustrated for a long time, or give up.