Hi Jeannie,
I am also enjoying the new Focal Series on alt processes. So far I have the gum, cyanotype, carbon, and gravure, :-)! I also have the latest edition of Christopher James Alt Photo Processes book.
I will confess that I am not as skill a gum printer as you sound like you are. I don’t know the process well enough to feel confident, yet, in changing the variables you mentioned.