That's one butt ugly board you have there...son
Listen, I can save you some work...
buy 1/2 Baltic birch ply wood...
It has 9 plys, and is use by Cabinet makers to make drawers
Why because it has no voids (what you were filling on the edges)
so, forget the two layer thing.
Do this spray down your drive way with hose, and place your cut out shape on the wet spot
and walk away....
Next day, you'll have rocker, put the straps on.....done
Congrats though, that's thief proof, kudos
Yeah thats good, but you have to BUY something. I happened to have all this stuff laying around (including glue)