I had a 17" CRT. I kept it for a long time but frankly once it starts fading you cannot adjust it. Believe me I tried! I tried for quite a while, actually. Then when I got an LCD I could compare them. I used them side by side because the LCD has a terribly slow refresh rate (it still does, sadly I don't have a better one yet). I could almost get it to match the color on the one next to it, if I only went for "at a glance" viewing. It wasn't perfect, though. It also weighed a ton and it was almost 2 feet deep. It took up most of my free desk space and was a general nuisance and massive dust magnet/heat source.
You can tweak some of the colors.. You might be able to boost the brightness color as well, but if you put it too high, it will only stress an aging piece of equipment. If you bring back fading red, you might increase too much green content. If you try to boost the gamma, you're going to lose definition in any of the greys and shadows, etc...
I would say just do what you can with only a bit of effort put in. Otherwise you're wasting your time for no improved results. Just realize it's on its way out, and that you won't be able to compensate for all the shortcomings, and when you get a new LCD you will wonder why you waited so long.