I don't see the point in recording the drums audio and midi at the same time. If you record midi, you have full control on changing drums or drum parts etc, and quantising out any bad errors (you probably don't make as many as me!). You can then explode the parts to different separate tracks and bounce those parts to audio in Studio One, thus giving you total control over the various drum sounds. If you record everything to a stereo audio track, you are stuck with all the drums within that track. Therefore, I don't see any point in it. I have certainly never needed a reference track.
I don't have any noticeable latency. there is definitely no latency on the midi side. With the Studio 192, if you select zero latency on the audio monitoring track, there is no latency. With the Quantum it is much the same.