Ok.

Do you have a decent T/S?

Yes
If so, do you also have a dado set?

Yes
Just curious, why do you want the ply pieces to interlock?

It's my table, I want it this way. As I explained in my second
note, I might have to dismantle it.

What is the ultimate purpose of this structure?

Support 1/2" plywood (4x4) with about a 50 lb load - tops.

Will await your response.

I await yours.

MJ