My piano skills are the weakest part of my conducting/rehearsal technique, so I'd like to work on them essentially starting from scratch. I don't have the option of a piano teacher, so I'm looking for method books or suggestions on what to practice that will help with my goals:
I'd like to be able to play through, say, a typical short 4-part Palestrina motet or a Bach chorale up to tempo with good accuracy after a couple of tries, with the eventual goal of sight-reading that kind of piece. My theory background is good and I can work out on paper a figured bass, identify chords and progressions, etc. I know more theory can only help my piano, in terms of being able to anticipate more of what's going on in a piece so I can play by "skimming" in a sense. My biggest problem right now is getting my hands to work together, and to some extent reading bass line quickly--I've only ever sung treble and played seriously instruments that are notated on treble clef, so I'm still slower in other clefs after all this time.
So, I'd like something like an "adult piano" book, but one perhaps for people who have theory background and experience on other instruments, and repertoire-building in terms of performing myself not being the goal.