I wouldn't worry to much about using WD-40 either for just cleaning
or exclusively as a lubricant.
I got 52,000 miles miles out of my chain by just spraying WD-40
on my chain every time I took a break(my bad knees make this an
hourly routine.) I never "cleaned" my chain unless I ended up riding
on gravel roads for a length of time. The only time I applied any
additional lubrication is when I knew I would be gone for several
weeks time. Then I just coated the chain with some of my old
Amsoil synth oil before I left and cleaned it off with WD-40 when
I returned. I did this twice I believe. Maybe cleaned twice too.
My chain still looked good when I changed it but was starting to
show some signs of kinking when not fully "lubed" with WD-40.
I've never experienced the dreaded red dust that seems to indicate
your rings are drying out and disintigrating. My guess is that the
lite oil and aromatics in the WD-40 probably kept the rings soft
and plyable and may have replaced/reinforced any lubrication
behind the rings. Myabe not. I don't know.
What I do know is that I get a LOT of miles out my chains using
just WD-40 and I'm "guessing" that there is nothing in the product
that destroys o-rings or cause problems in the way in which
they function.