Subject: max gvwr for Ambassador ?

Anybody know the max carrying capacity for an Ambassador?

My son and I weigh over 400 lbs and I have a bad feeling
that the max capacity of the Ambo is under 400lbs. The shop manual
is silent on the topic.

I realize that the tire max load is part of the equation -- is
that all there is to it? bike + people / 2 <= max tire load ?

Thanks,
Bill Dudley
New Jersey