Im not a gunsmith.
From my understanding on the way the trigger pack is constructed, there are a lot of areas for improvement everywhere. I tend to avoid reducing the hammer spring as much as possible to prevent ignition issues. (I had a lot of issues with an AR hammer spring lightening trial once).
It seems to me that having a competent gunsmith go in and polish all of the surfaces for the trigggrpup is the next step after changing out he trigger spring, pins, and trigger on the EVO. I bet they can shave a pound or two. If you have done that, you may be at a plateau.
ETA: of course, there is the CZ Custom trigger pack that has far less play and is adjustable for takeup. That could also be a good next move for you.
(Personally, i am more intered in a binary trigger option.)