Is this for in-home-defense?
If so, I would recommend spending the money & getting real tritium. I know you said it's not an option right now, but, one day (maybe soon) it will be an option....on that day I would buy tritium sights.
Okay, but what can you do today? If it is for use in the house (God forbid), you may be able to set up a situation where you have an advantage. Outside lights with motion detectors. Secure locks on your windows. Alarm system.
Another thing is the light switch that activates when someone is in the room. If, for example, you have a livingroom light switch by the back door, replace it with one of these. Then, if someone gets in the door, the lights will come on....that alone will scare off most theives. If they stick around, you'll see what to shoot at.
There are quite a few inexpensive things you can do at home.
If it is for away from home protection, the paint might work. I'd still save up for tritium.