I used the SnF drill for the first time tonight and boy, was it impressive. The girls were talking about how much stronger they felt, and the ball really popped off the bat. We hit into a big vinyl screen, and it sounded like the 1812 Overture.
Tips for newbies like me: if the hitters don't bend their inside knee and get over their inside knee, they won't be able to coil as much. Also, the tendency at first is to swing around their bodies (MTS was right on with both of those warnings), so I had to demonstrate going "out" from their bodies to get stronger (go "through it" not "around it"). I told them to use their outside foot to catch them as they fell forward.
We then hit straight away on tees up the middle, and you could tell the difference. I can't wait to see what this will do after we're at it a while and the girls build that muscle memory. I'm sold.