Folks

thanks for all the kind answers. I will digest soon, but I have a busy time with work for next 7 days so I will not be able to experiment and perhaps ask further questions till after than.

I just get confused with additive and subtractive colour models.... but:
If your print is too cyan, you want to do the wrong thing, which is to add more cyan.
is exactly what was throwing me I think ... once I developed an 'adage' "that when it doesn't seem to fit its because everything is opposite to what I'd expect"

this especially holds true in my work (computers)