Welcome to TBN - here is what I put on my B21 - its some 1/2" plywood sandwich attached to the right side frame also a 1/2" thick steel. Simple but effective -now the saw doesnt need to ride in the bucket of the FEL or BH and is easy to access.
The hood clears the chain / ammo box without the saw in the bracket and the ammo box holds a 20' 3/8" chain and a shorter choker chain. The lift arms are clear the saw by about an 1" .
Carl