I have Trijicon tritium sights on a Sig P225 (9mm pistol) and I can not imagine that that sight would be worth much on a rifle ... maybe they make some bigger (brighter) ones especially for rifles?
I think the idea of the plastic ones sounds pretty good, I worry about the durability, but I guess the hood on an SKS would protect it OK. Durability is the only negative that I can think of.
Saands