Got it. I'm thinking two cross-sections, three inches or so apart, on
either edge of the table (four total. maybe one in the center as
well? - though it will be interrupted shortly after the curve).
Reinforce (glue and screws ok?) with cross-members as seen in this
image - http://www.raygirling.com/images/closeup.jpg. Am I close?

Can I use screws as well as nails to secure the cross-member to cross-
sections? And where do I notch the other side of the cross-section?
Exactly across or shifted a bit? Please excuse my lack of
terminology, I'm learning as I go. So in the above image, if I have
another horizontal cross-section to join, would I shift the notch or
not?

THEN can I use Bondo??? Or will P-Lam take it's place.