With microphones, the only signal split I am aware of is in a true stereo mic. This mic is designed with two separate mics inside, positioned just right to avoid phase problems, and deliver a stereo reproduction of sound.
For mics other than stereo ones, the "pickup patterns" cardioid, omni, hypercardioid, and figure 8, are indicator of the mic's feild of "veiw". A figure 8 mic will send only one signal to the board, and it will derive that signal from the front, and rear of the mic. Omni's from all over, and cardioid in a heart shape in front of the mic. All mics work like this, and good ones(like the 414)have diagrams which show the areas of pickup, and the variance in frequency response off-axis.
I am not sure that a figure 8 is the best way to mic toms. You may find that mic a little more handy as an overhead in figure 8.
If you do mic the toms with it,(414 sounds great)
Then I would suggest cardioid or hypercardioid, depending on what other instruments you hear with the mic. If you are switching patterns, then be mindful of the difference in gain from one setting to the next.
Hope this helps you out. :tu: