Reply by TCCcabinetmaker

I’d suggest 3/4 ply, but yes this will work and shouldn’t have to be tounge and groove. Use plenty of glue, and as long as you don’t put breadboards at the ends, the movement of the wood should not be an issue, as long as your lumber is already stable.

-- The mark of a good carpenter is not how few mistakes he makes, but rather how well he fixes them.