Here's what I do:
-hold spring between thumb and fingers in one hand. Thumb braces spring where cuts for 3 leaves ends.
-Use other hand on tips of springs and bend.
It's not a really critical operation. The spring will ultimately bend where it wants to, and will rebound back from most bending. A little goes a long way. Be sure to prep the tips of the fingers by polishing and beveling them at the points where they'll contact the sear and disconnector. Remember that your spring tension is what largely determines your pull weight, not the drop in components. Keep the sear and disconnector fingers at about the same weight.