So how do I recover from this foolish assumption?

[Steve Roxberg]

Apply thin strips of maple to the outside of the top to match the bottom. It will also cover those screw holes for you. Just make sure you rip the thin strips on the OUTSIDE of the blade rather than trapped between the blade and the fence.

Agreed, this would be my approach.

[Keith Hankins]

My immediate thought as well

+1 would do it in a heartbeat, and hand plane down to match the angle. Done. No one will notice

[Chris Hachet]

Apply thin strips of maple to the outside of the top to match the bottom. It will also cover those screw holes for you. Just make sure you rip the thin strips on the OUTSIDE of the blade rather than trapped between the blade and the fence.

Exactly this.

[Rob Damon]

If the wood was final milled and you have no sketches or previous examples of the original intent of the look/feel of the box, then you might assume it was meant to be different in size for a reason. I would ask if there are other examples of boxes that he had made previously, so you can use that as an example, so the work is more his vision rather than your vision/guess of his intent. After all this is suppose to be his work and not your work.

Without examples some options:

Why not just leave the dimension difference and add a bead board (1/4") thick between the two as a transition strip. Make it proud of both boards of a contrasting wood. If you don't have any contrasting wood, just stain/dye some maple strips a dark color.

Another option would be to rabbit the bottom of the maple and rabbit the top of the cherry and interlock the top with the bottom and simply round over the excess overhang of the maple as a edge detail.

I would also remove the screws in the top piece and dowel it with cherry pins instead.

Just some thoughts.

[Wade Lippman]

I messed up and gouged one of the tops, and after sanding, it is a bit too small.
BUT... shimming the gouged top makes it fit the oversized bottom.

Two screw ups with one fix.

BTW, it is going to be painted, so the screws won't show once they are filled; etc.

[Stew Hagerty]

I messed up and gouged one of the tops, and after sanding, it is a bit too small.
BUT... shimming the gouged top makes it fit the oversized bottom.

Two screw ups with one fix.

BTW, it is going to be painted, so the screws won't show once they are filled; etc.

I don't really follow you about how gouging one of the tops fixed the problem, but not matter. If it did, it did.

As for painting... The boxes are a mix of Cherry and Maple. Why on earth would you paint over that beautiful, expensive wood?
Typically if something is going to be painted a relatively i expensive wood such as Pine or Poplar is used.
Besides, the tops and bottoms were made from different species for a reason.
I mean, hey... It is your project and you can certainly paint it if you choose. I personally just think it would be a shame to hid÷ the beauty that is natural Cherry & Maple.
But then, that's just me.