I'm having trouble understanding the science of getting the right length stem and bars.
A longer stem makes steering more sluggish b/c of lower leverage on the steerer tube, as is the case with longer bars (is this correct?). But then again, a stem that's too short won't provide enough leverage, thus reducing the efficiency.

Is there a way outside of "go with what feels best" to determine the most efficient combination of the two?

I'm putting a Shiver on an '04 Bighit comp and want to get the steering as tight as possible, given the length of the fork.