I find it a bit cumbersome to try to use blocks to help organize an ‘assembly’ of pieces being actively concurrently designed, specifically the way editing a block requires locking-out the rest of the model or exploding a block and redefining it, and if you use a separate file all geometry is in it whether hidden or not. It might be a bit slicker to set a layer as the source of a block, and just continuously whatever is turned on in that layer(aside from instances of the block itself) is updated as the definition.
Jim