Sounds a little cheap... but I took some of my daughters bright orange nail polish and put a dot on the front site of my compact 22 and it makes a big difference IMHO.
Thanks for the suggestions. Both pistols are my father's. Trying to get something that will work better for his eyes. Will most likely try the paint first and have him look at the TFO sights and night sights I have on my M&P pistols when we get a chance.