How fast should you practice?
I advise my non-pianist students to practice their parts at the tempo they can play the part. For me, circa college, that was about 30bpm. It’s faster now, but at the time, that was the perfect tempo for me to practice my music.
Practicing slow forces accuracy, and it allows time for your brain to make intentional choices, rather than unconscious ones. I discover so much about my singing when I slow down to practice.
What about the pianists? Well, you already know the value of deliberate, slow practice…so even though you can play your parts plenty fast, slow down anyhow.