Thanks Pete, I'm gradually getting there!
Just seems a little odd that if in retrospect, I wanted to add a new axis to all modules, I can't do it. For example, although I having been simming for many years, I have only just got into MSFS very recently. On my rudders, Virpil throttle and stick, I have about 15 axes, and at this stage of my knowledge, I have only set up the usual stuff like throttles, brake, elevator, flaps, etc. At some point soon, I might think, oh, yes, that axis would be useful for task x. It would seem that I would have to add that into all profile manually rather than being able to add it into all in a 'general' category.
The flexibility is great, as you say, as it's possible to define and refine throttle behaviour for each aircraft - just like DCS - which MSFS can't do.
Could adding an axes for all aircraft after adding it for one be done by editing the ini file? Looks possible from my casual look through.