In article ,
Silvan wrote:

5/32" oak or maple, supported entirely around the rim and accross a
small span is surprisingly ridgid; quite a bit more rigid then plywood
for example. Just a though to save you some effort...

What about wood movement? I have some pieces of BORG red oak "hobby wood"
from and old project that never got built. They're probably about 1/4"
thick, and after several years in my outdoor shop they're severely cupped.

K, I went an played with a little really thin maple. I gotta admit, 5/32
isn't much; Still, in anycase that is all that will be supporting it.

Think the wood has moved all it's going to move? I could plane them to
5/32" and use them as inserts. Be a helluva lot easier since I don't own a
decent router.

I haven't a clue if they are done moving, but if they move a little a
few months from now, no great loss. You could try plane a little today,
plane a little in a few days...that seems to work much better. Actually,
plane most of it today, plane a little in a few days...