Jay -

Your twin mom is letting down on both sides if she's letting down on one.
The difference is either in actual supply or in the ability of the flange
to access the milk (which will ultimately affect supply).  She could try
the large glass flange.  A mom who was donating pumped milk found she got
twice as much from one side as from the other, yet her baby seemed to
swallow equally on both sides.  Sure enough, when she tried the large
flange, it hurt on the higher volume side, but got more milk out on the
lower volume side.  Just different placement of sinuses, I suppose, and her
baby didn't seem to notice the difference tho the pump did.

And a voice of dissention about the wet-nursing:

An experienced nursing mother has fine-tuning built into her hands and her
posture - subtle shifts of breast and baby that enhance a latch and that
can't be imparted verbally very well.  She may also have slightly "easier"
breasts than a given mother, that can act as a sort of bridge to the
mother's own.

I've had a few vicarious experiences with breastfeeding-impaired babies
being wet-nursed.

One was the poorly-nursing premie baby of a mom who just couldn't pump
well, tho baby needed the extra.  Mom was tense, baby was hungry.  Her
sister nursed the baby a few times over a day or two, gave it several good
full bellies-full while mom caught up on some sleep, then mom and baby were
off and running.  She was *vastly relieved* to have her sister help out,
and nursed into toddlerhood.

One was a non-latcher.  The mom had a friend try, and baby still refused to
latch.  Mom felt better, knowing it was nothing *she* was doing wrong, and
baby began nursing at 5 or 6 weeks.  Baby had been deeply suctioned at
birth...

One was a premie whose skills seemed to improve - and whose mother's
outlook improved - when an experienced friend nursed the baby and told the
mom her baby was sucking normally.

The last was a baby who had latched at his mother's non-elastic,
flat-nippled breasts until given a bottle at a couple days of age.  We got
him nursing again, but his clamping caused mom to take him off repeatedly,
and he became an aggressive non-nurser.  Weeks went by, with no progress
(this was years ago; I hope I'd do a better job now).  She finally asked a
friend to try.  The friend held him snuggly in a nursing position, standing
up, and started to bounce.  The higher and harder she bounced, the better
he sucked, and he ended up nursing.  Still wouldn't nurse from mom, though.
They arranged to spend an afternoon together nursing each other's babies.
(The older baby was a little puzzled by the new mother's relatively
featureless anatomy, but finally sort of shrugged and started nursing.)  At
the end of the afternoon, the new mom reported an entirely different suck
on her finger - much more of a drawing motion than before.  But the
emotional toll was too much and she opted ultimately to bottle-feed.  I
will always wonder what would have happened if the wet-nursing had started
before the mom was so worn down emotionally.

The lessons to me?  1) Each case is different.  No hard and fast rules.  2)
Nursing *can* be learned at a breast other than mom's, because the hands
are skilled and because any breast is going to be more like mom's breast
than a bottle, finger, or cup is.

Diane Wiessinger, MS, IBCLC  Ithaca, NY