Agree with 'Rally'.
I, too, have found long, light weight underwear the most comfortable for touring.
Because of the thin, but warm, light weight construction, it does not bunch up and
create pressure creases on your thighs and bottom.
Nothing to stop you from having a full length set for colder days and perhaps a
second set, but shortened to around your quads , for the warmer days.
Just a thought.
Cheers,
Wayne