The potential problem with moisture content is that the piece would travel from a humid to an arid environment. Seasonal changes in Nevada, once the table is there, would cause minimal movement.
Top and bottom finish are identical, and each has equal number of coats. MC of lumber and shop are plus or minus 2%. Top is attached to base in slotted screw holes, and only though a structure in the center 18" of the table.
A major challenge, and perhaps the single reason I'd turn down the commission, is that the table top "floats" above the leaves on a stow-leaf table. On a 54" top with an 18" leaf on each end, the table top is attached only to an 18" fixed structure in the center.
This means that when closed, the table top rests on the closed leaf, which rests on the table base. when the leaf is open, the slides rise up and support the top. (This is why the leaf can be (and must be) the exact width of the table top). This floating isn't a problem on a 42" wide top.
The one thing that might save this job is breadboard ends, which I would maximize. Also, quartered stock would influence my decision if I can get the customer to agree to it.