Having made the box bottom too big for the top I made another top, the waves were stronger in look but lost the watery look however the top was a bit big and was able to sand it down to fit tightly, the sides are engraved in a woven pattern that I very much like that was also used in the Greenman box.
It is hard enough. Harder? But definitely not oak. My impression was maple and the hardness is similar with very tight grain but individual very fine threads that make it very not maple but nowhere near as fibrous as white oak much less red oak that was recently pointed out to not be water tight unlike white oak.
Apparently cheap oak barrels where they were not careful to be all white oak would be a problem filled with alcohol as they would leak through the wood.
6.4" x 3" x 2.4 " the top is 0.35" the rest is .125 the bottom is Maple and the top is IDK. I have a batch of 1/8 and am thinking still it is a bit thin but the 1/4 " is a bit thick so may be trying the 3/16 when my backlog of wood gets a bit thinner.