Re: Where the slave beater strikes...
Jeff, I'm no expert on pedals, but I can answer your question regarding striking position. Striking the very center of the head delivers the cleanest fundamental note. The further you move away from center, the more you involve higher tones. On bass drums, you only need to move a small distance from center to get a distinctly different sound & response from the drum. Sometimes, moving away from center is used to offer benefit. For example, if you're a player who buries the beater, moving off center (in any direction) will offer a touch more head sustain.
I hope this helps,