In my opinion,if you are asking here about how to do a trigger job,go easy!!
I would not use a power anything on it.
While someone who really knows what they are doing can use hard,flat smooth stones to improve the surface finish on sear and hammer notch features,any change of angles or rounding of corners is detrimental.
At this point,I'd say do not touch the sear or hammer notches,even with a buffing wheel.
These surfaces will wear in with time,and develope a burnished,matched fit to a degree.
Now,on the flat sides of parts,where they contact the frame,etc,a floating off of high spots,just a few strokes,with a fine india or arkansas stone is good.and a barely visible corner break on non-funtional sharp edges can be stoned on,just a couple thousandths radius so its not a scraping edge.
Don't stone off low spots,that just makes a loose,worn out gun.Knock the tops off high spots.
I do not know if they are still available ,but the Trapper spring kit has worked well in my Ruger since the 70's.You can get a one step lighter hammer spring,.too.
Try that much.It won't be a Jewell trigger,but it will be much better,and safe and reliable.