I have a TRR8. I put in a Jerry Miculek spring kit and followed the instructions in his video to reduce mine to about 7 1/2 pounds. Works great with Federal primers. I haven't tried it with any other brand.
How to install a spring kit (trigger job) with Jerry Miculek - YouTube
Inside the frame it was so smooth I didn't do any stone work. I'll open it up again after a few thousand more rounds and see what the wear looks like. Right now I'm pretty happy with it.