In terms of Tritium visibility, I was browsing MB-Microtecs. They are the OEM for most of the worlds Tritium products (vials used in Sights, Watches, etc)
https://trigalight.com/tactical/
I came across this interesting model; a Tritium insert with a Convex sapphire lens to double the brightness of the vial compared to a standard flat sapphire lens as used in most Tritium sights.
https://i.ibb.co/0qz0ddG/Tritium-Convex-Lens.jpg
I'm curious if any of the Sight manufacturers have caught onto this new model, and if any of the current sights are using this convex feature. A brighter tritium sight would be awesome.