Since nobody else has answered . . .
You can get spring kits to help lighten the pull. However, inexperienced amateurs messing with the springs often leads to light primer strikes, meaning a failure to fire. Dry fire it a lot and see if this helps. If not, get a gunsmith to give it a professional action job which means polishing and not just clipping a spring. SW is an obvious choice. As far as local smiths, I can't help.
My real question is, why bob the hammer? There are only two reasons I can think of to bob a hammer:
1. For pocket carry so the hammer won't get caught in clothing. I can't imagine pocket carrying even a short barreled 686. They are just too big for any of my pockets.
2. Certain police agencies have bobbed the hammers to make sure the officer doesn't fire single action. They wanted a long, heavier trigger pull to avoid accidental discharges under stress. If you don't want to fire single action, that's fine. You don't have to bob the hammer, however. You will also likely lessen the resale value. You'll also miss the joys of a carefully aimed, deliberate shot hitting a target at medium and long rage distances.
