For many years, I have run a tritium front with a Heinie or Warren one dot/bar tritium rear. Recently, I was handling one of my wife's Glock pistols with HD sights in the dark, and felt the two dot tritium rear sight was more usable. I now see that Warren offers a Glock rear sight with two tritium dots as opposed to just one.
What are your thoughts on one versus two tritium dots for use in dark conditions?