Snyd hit the nail squarely. I have had several Redhawks over the years with trigger jobs. I don't know what you find heavy, the single action, the double action or both. The gun can be smoothed up which will lighten the pull somewhat. Single action can be reduced some by playing with the sear angle some but if not careful one will get pushoff.
Gunsmiths that work on Redhawks are Bowen, Magnaport, Grant Cunningham and Dave Clements among others. Generally, with their tuning the double action can be taken down to about 9.5 to 10.5 lbs and single in the 3 lb range. This compares favorably with tuned Anacondas and Dan Wessons but will never be as light as a Smith & Wesson 29/629 that is tuned.
The single spring limits what one can do as you can lighten it and it will work with single action but misfire in double action. In the past I have played with the Wolff spring kits on tuned Redkhawks. For me anything less than a 14 lb spring (stock is 17) got misfires in double action with some ammo. With Federal primers and whatever Corbon uses in their ammo and a 12 lb mainspring the double action on my Rh was 8.8 lbs and it worked but not with some other ammo (misfires). Going to the 14 lb spring solved the problem. If I was going to use the gun in the wild I would use the 17 lb mainspring.