Managing Very Large Multilayered file

I have a very large multilayered file (5760 X 570 / 19 layers) and am at the max size because PS won't save any images over 4 Gigs.

I thought perhaps that using linked smart objects might make it a lighter weight file but it is looking like it may not reduce the size. I don't want to break up the file because I need to see how all layers relate to one another and make changes on the fly. My process is to Place a linked file into the master document and then need be duplicate it (command J) rather than place the same linked file again. I am not getting any efficiency this way.

I would deeply appreciate any thoughts on managing large multilayered files to make it workable.