i have one channel per note of the bassline (sometimes plus extra-channels for notes overlapping with the kick) all routed to one bass bus, which is then routed to the knb bus.
i often do a boost at the second harmonic and a cut at the fifth on the bassline. if the notes change these eq bands are off and the sound isn't as clean. thanks for mentioning keytracking. i haven't really thought about that before for the bassline.