For "easing" drag marks, I high-polish a band around the cylinder and the head of the cylinder stop, finishing off with 1500 grit, wet. Tape it off, and matte-blast the rest.
THis fellow does a nice pistol:
http://www.grantcunningham.com/gp-100_100906.html
However, as Flatgate mentions, a real job would involve fitting the stop. In their heyday, S&Ws were noted for the absence of drag marks, but in the age of EDM/MIM mass production, you won't see factory guns like that.
I fixed up my Alaskan, and have a faint mark starting abut 1/2 way between each cylinder. A dab of Tetra grease on the stop head, with each cleaning, will keep it to a minimum. One of these days, I'll get some pics up.
Edit to add: on your blued guns, I would put some elbow grease into polishing the cylinder stop, and apply a spot of grease with each range session.