I wouldn't do any trimming on that factory spring. Direct aftermarket replacements are cheap enough that experimenting needn't be ruinous.
Generally, I agree with Jim K. If it's supposed to be for self defense I'd leave any modifications to a qualified and experienced professional. Personally, I'd rather shoot it enough to really break it in with what came in it (at least several hundred rounds) to see how it smoothes-up before considering messing with anything. You'd be surprised at how much improvement some use along with proper cleaning and lubrication can make. Let's face it, in most cases a basic "action job" is just paying someone to put the right amount of wear in the right places for you, as long as there's nothing amiss with the mechanism.
I have a Taurus M-94 .22 revolver that benefited a good deal from a bunch of shooting, but I wanted it "better". I bought a Wolff "Shooter's Pack" kit from Brownell's that contained a reduced power (9#) hammer spring and two trigger spring options (6.5 & 9#). With some experimenting I was able to get a very satisfactory improvement in both DA and SA trigger action without any discernable loss of functional reliability.
If you must tinker, this route is the one I'd recommend. A small investment in a couple of special tools will go a long way to smoothing the DIY path.
Properly fitting screwdrivers. If you don't have 'em, get a set. Hardware store items will chew up the slots and mess up your pretty finish big-time if they slip.
Rebound spring tool. If you anticipate doing any tinkering or detail stripping the lockwork on any revolver with a S&W-type action - get one. It'll save you untold grief and frustration, not to mention hours of searching the floor for that tiny, strong, essential spring that went "spwiiing!" while you were trying to get it out or put it back. Brownell's stock number 080-666-000and, at $14.08, cheaper than a bottle of good whiskey or Anger Management therapy.