Jake, I notice that most articles call for 8-10 glasses of water each day. But I guess it depends on what size the glass is, doesn't it?
My hubby was told to dring 2 liters daily, but not for stones, just kidney health. I was once instructed to drink 3 L each day for kidney stones that showed on a CT image (I have a transplanted kidney). But now the kidney stones are gone (don't know how? don't know when?) and I am instructed to drink 2 L.

Mayo Clinic Minute: Tips to avoid summer kidney stones
https://newsnetwork.mayoclinic.org/discussion/mayo-clinic-minute-tips-to-avoid-summer-kidney-stones/