When the magnification is assigned to F1 or F2, pressing those buttons toggles it on and off. I have them set for 50% and 200%. This is easier than having to back out of the magnification and is super quick. 200% is most useful for fine focus, and 50% still gives a decent boost but still keeps enough context around the subject.
I prefer to have Fn1 assigned to 100%, I can always switch to 50% or 200% by pressing the "-" or "+" buttons on the back of the camera.
I have assigned Fn2 (+dials) to focus mode selection, I can switch to MF-AFS-AFC (also displayed in the top line in the viewfinder), without having to call up a menu.
It's not so bad to have the index finger on the shutter release and the middle finger on the Fn1 button: position of these buttons seems to be designed for my hand! YMMV.
One feature I would like is to have a menu option to affect the zoom behaviour, something like
f8 Zoom behaviour
with these options:
-Release exits zoom mode
-Zoom mode unaffected by release (to exit, press again zoom button)
This would be nice when shooting sequences, it's annoying when shooting in CH that upon the first release it exits zoom mode.
Ciao from Massimo