you can "snip" a coil off of the tension spring (one small spring inside the other). start small (1/4 to 1/3 a coil) and cut more as needed. it should be a double spring. snip the larger one. i think the lowest that trigger can go is somehwere around 3lbs. you should be right at about 5.5lbs right now correct? make sure you check the sear so that it isnt slipping
I think it best to take it to a competent gunsmith. The charge is about $25-40. well worth it, and he will make it what ever your want. My gun gives you about 2.5 pounds, after you feel it if you want it lighter, he does that free..