In order to get the lighter trigger pull, you have to put in a lighter mainspring for a J frame, or back off the tension on K,L or N frame. The lighter weight of the hammer allows a lighter spring pressure to get it up to speed in time. Also, a lighter tension of mainspring allows for a lighter rebound spring that still gives a snappy trigger return. You can shave off a pound or 2 of trigger pull just with the rebound spring.
I think the best you're going to do to lighten a J frame is to get a duty type spring kit from Apex or Wolff. If the spring kit works with the hammer spur on, it will be only slightly better with it bobbed. There isn't much weight in a J frame spur. To me, the best reason to bob the hammer on a carry gun is so it doesn't hang up on your clothes on the draw when you desperately need it RIGHT NOW.
The spring kits are a noticeable improvement in trigger pull over factory, but make darn sure it works every time with your SD loads before using it for EDC. Federal makes the lightest primers, so it might be good to use Federal SD factory ammo.
The only caveat is this only works on centerfire guns. The rimfire ones need a heavy hammer and spring to crush the folded over rim. Apex Tactical has a new rimfire hammer for 617s, (K frame), but nothing for .22 J frames.