There are two forms of resistance in your pedal. The tension in your spring and the weight of the beater head.
I would start by lowering your beater heads a tiny bit at a time (like "1/4) until you find the resistance feels right. When you've gone too far, the pedal will feel very light and it'll be hard to do a good fast kick with one foot.
At this point you can either raise the beater again or begin tightening your springs to compensate.
Play around with these factors long enough and you'll find that magic balance between your foot and the pedal, as your feet get stronger you'll have to make more minor adjustments, but your
DW will certainly crap all over a Gibralter.