Yeah, each side will be rabbeted, but a rabbet is usually employed at a right angle whiie shiplap is planar application of a rabbet.

I was originally going to equalize the thickness of the sides by rabbeting them with a roller type undercut bit, but found a lazier/safer method in varying the depths of the rabbet of each side of the plexi.. It would be too easy to tear out an inside corner of the case with the former method.

I'm considering a bevel on the plexi edge so that it protrudes a bit above the surface of the case, but that might prove problematic in terms of scratches on the plexi and adding another level of complexity.

Now that I've been looking at the thinner clear plexi side for a few hours, I might take the most simple approach of all. Putting the bevel on the nine sides of the Bucket by hand by scraping won't be bad at all. The bends in the thinner plexi will be much less noticeable in terms of distortion, less obtrusive in terms of clarity and the sub-surface glazing would less prone to collecting scratches.

hrmmm . . .