Any "real" F7 clutching gains...

Anyone out there had any real clutching success with the F7? I have a couple hundred miles on mine and have just started experimenting by adding some weight (2 grams) to the primary with a stiffer spring, and switching to a steeper helix. I have not had a chance to test side by side to see if I have made progress as of yet. In my humble opinion, I think the stock clutching is pretty close.

Any other opinions, theories?