I believe that anything from just cut to final air dry MC will work well. Many people have had decent to good success even with bone-dry kiln dried stock (using bending jigs, backing straps, and selecting the best material). Everyone that uses air-dried material seems to have an easier time with bending, for whatever that's worth.

The more "green" the wood is, the more flexible it will be on its own.

: what do people think is the ideal moisture content for white oak used in
: steam bending (will be for ribs; probably around 3/8 thick by 1-1/4 wide)?
: is 10-15% too low?