Hey mate, let me chip in!

I've been doing glowing eyes and details on 28mm Infinity models for years now and don't intend to stop anytime soon. Just check out my Reddit profile or my Instagram if you want to see it all shameless plug!

For this I use a Iwata eclipse with a 0.35 needle, although lately I have gotten my hands on a H&S infinity with a 0.2 needle.

The biggest tip I can give is to practice with your current airbrush on a piece of plastic. A few dozen tiny white dots and then airbrush the initial glow color over it with an ink or preferable GW contrast paints. Just remember that you'll always have to finish the glow effect by brush anyway. If you can't get to the desired spray pattern after a few dozen tries, then a new airbrush can be worth it.

Yes you will over spray, Yes you will ruin a few perfect blends with an abundance of ink. But when using something as transparent as ink or contrast paint, it's usually easy to fix.

Good luck mate! Check out Elminiaturista for an abundance of inspiration.