If it's hooded, painting the sight likely won't help since it'll be in shadow and the paint will not show up.
A good sight paint is model airplane paint.
It comes in small, inexpensive bottles, and in virtually any color you could want.
Some colors to experiment with:
White.
Fluorescent Red. Apply a base coat of gloss white first to serve as a reflector coat and make the paint really stand out.
Bright Green. Bright Green is actually the most visible color.
Bright Yellow.
