Default clip fade length

I have created a keyboard shortcuts for 'fade in normal' & 'fade out normal' and linked them to the 3rd and 4th buttons on my trackball. (Would be great if I could map both to one button click. Is there a way to do this with some kind of action or macro?)

The fades by default are set to cover the full length of the clip. How do I adjust their default length to something like 5ms to apply to clip edits?