Advice on Multiple Masking workflow

Ok I'm new to fusion and am wanting to get some suggestions on a multiple masking workflow.

I've investigated nMask and for whatever reason I'm not getting clean masks.
What other workflows do others use?

I'm using 3delight as the renderer and it can output masks as separate passes which are giving excellent results.
What I liked about the nMask macro is being able to quickly pick from a color on the image.
If I was to bring in a layered tiff or exr file of masks - is there a quick way of picking which mask I want to use?

thanks for your time..

(*Sorry wrong topic*)