I am in the process of upgrading the stock 3-white-dot sights to night sights to go along with my TLR-1. Here is what I am aware of right now for M9 sight options:
1) Drill and insert tritium vial into front sight, replace rear sight with 2-dot tritiums
2) Drill and insert tritium vial into front sight, take sharpie marker and black out rear dots
Any other ideas? I kind of like the serrated plain black rear sight (like the 10-8 sights), but I don't think any of them are compatible with M9s.