So for years now, at least since DAWs have given us the ability to move audio files around by infinitesimal amounts within a time line, I've both read and talked to other engineers about time aligning the overhead drum mics to the Snare and Kick...
I know there's also software available that can apparently time align those mics/tracks, although I've never used it.

I was listening to a current drum track and playing with phase switches while in mono. Listening to the low end it sounds the fullest with one over head switched out. The right from the drummers perspective. However, listening to the hi end I can hear a slight filtering type thing with this setup. From now on I will listen for this while tracking, but what adjustment should I make?