I use Medium 100%. Jason has stated that he designs his molds for medium.
The only time I add softener is when I need better flow into small appendages (legs, etc) and when I shoot it hot to improve flow..I get flashing.
I recommend the HD additive also for any wacky bait. You get the sink rate ...and a darn tough bait.. without any noticeable lack of action.
Shoot those 6" carrots with 2 tablespoons (use a measuring spoon to assure accuracy) per 4 oz you'll get the same sink rate as a salted Senko (according to Bill's calculations)...and a dozen or more fish per worm!