You are not going to get a light trigger pull with a J-frame. The shorter hammer stroke and the reduced weight of the hammer necessitate a stronger hammer spring for reliable primer ignition, and that equals a heavier trigger pull. A good Smith gunsmith (Nelson Ford) worked on my 442, and he explained this to me. It makes sense. Some lightening via work on the trigger rebound spring is possible, and smoothing the action via polishing of the internal components is also possible, but you'll never get the light DA pull that can be achieved with the K- and N-frames. It's a belly gun, not a target gun - you'll just have to get used to it.
John
John