I do something similar when doing step by step building instructions.
Basically, I have a main drawing module, which looks like this:
Then, I put all the drawing in separate modules, and call them from this
module. The reason I have == and >= is that I often have stuff that will
only be that way for a single frame (such as screws being shown not screwed
in fully), and then I use >= for the stuff that should remain in the