Go to a craft store and buy some fluorescent yellow paint (or color you prefer). Put a dot on the front sight and one on either side of the pack site (you might want to try another color for the back site). This will run you a couple of bucks to try. If you don't like it the paint comes of easily. You may have to put a few coats on to cover the black site color.
I have a Gp100 and i couldnt stand the front sight on my revolver. So i bought bright green nail polish and i love it now. I did the same thing to my oldladys glock and i shoot way better with the colored sights. And if you want to try a different color just use some nail polish remover and try what floats your boat.