I just ordered this bamboo octogon one (there's also an acrylic version available). Someone answered my question about inner dimensions - the inner octogon is 4.5" wide. I don't have the dimensions of the 8 other pockets, but eyeballing it from the photos and from knowledge of the center, I'm estimating they're roughly 2"x2". Given they're irregular concave hexagons, though, it's pretty hard to size estimate them.

If that doesn't work out, I'll likely order the one you linked. Thanks again for your help! I might not have found this one without your suggestions :)