Adding hand animations to existing animation

Hi, I already have an Idea about this! but would like it confirmed before I proceed.

I have made some hand poses on the default mannequin which is still in its neutral bind pose.
i want to be able to make the hands change to these poses without affecting any other animation thats already running, just affect the hands only and avoid the whole skeleton going in to bind pose with he hand animation I created.
Is the layered blend per bone method the best Approach?

also want to know