Is this it?
His footage at the end looked pretty good. Using screws to mount it though is unnecessary and adds weight and complexity, some good double faced foam mounting tape (the permanent, outdoor type) would be easier, lighter and also help to further isolate the assembly.
He used the solid plate on top, the slotted one will probably fit right between the Syma tabs that he removed, Banggood shows it with 2 slotted plates.