My usual process for mixing wheat doughs is to mix briefly just to wet
all the flour, then let it sit 30 minutes to hydrate ("autolyse"),
then knead about 5-10 minutes (in a KA mixer) until it's smooth and
elastic. (This replaced my old method of mixing for 15 minutes
straight with no autolyse; I find that the autolyse method gives the
same gluten development with much less mixing.)

My last attempt at a dough with any substantial portion of rye flour
resulted in a grainy, sticky, gummy mess. This was before I started
including the autolyse phase. I've just been reading through the rye
sections of various books and I've seen some conflicting advice,
though the unanimous opinion is that rye can't handle much mixing.

One questionable thing I read is that the pentosan gums in rye will
tend to "gobble up" the water before the gluten has a chance to
hydrate, resulting in poor gluten quality. That author recommended
initial mixing with only 2/3 of the water to make a stiff dough, then
an autolyse, then mixing to a smooth ball. Then the remaining water
is added a little bit at a time, kneading after each addition until
the dough is smooth. I'm afraid I don't see the logic in this method;
why not add all the water at once? How does this help the gluten get
more of the water than the gums? Any thoughts?

I'd be interested in hearing other advice on handling mixed
whole-grain wheat/rye doughs, with anywhere from 10%-50% rye. Also,
opinions on the right hydration would be appreciated; my standard for
100% whole wheat is 67-70%. Rye ought to be able to absorb more, in
theory, but then my (limited) experience says that it will be very
sticky, so I would tend to want to make it drier.

One more question -- I understand that acidity is key to rye doughs.
Is it critical that this acidity be present at mixing time (i.e., from
the pre-ferment), or can I use a small amount of not-too-sour
pre-ferment and rely on acid production during bulk fermentation?

--
Randall