Figure one cup of water per oz.
Remember one unassailable statistic, as explained by the late, great George Carlin: "Just think of how stupid the average person is, and then realize half of them are even stupider!"
"I would like to die on Mars, just not on impact." Elon Musk
FYI, 2 oz of Centennial in the Pale Ale makes for a really nice IPA. Good hop aroma and bitterness without a grassy flavour.
I'll give it another week in the primary to settle out before I keg it, but it's going to be a really nice beer.