From my limited experience (I'm in the middle of my first SOF)
the grain orientation is more important than whether or not
it's kiln dried. I posted earlier about the problems I had with
bending ribs. I was using green "bending oak". Every one of
my ribs broke when I tried to bend it. I think went out and
bought some ash from a hardwood lumber supplier. It was dry -
not sure if kiln dried or air dried. This second time around
it went great. I ended up breaking 8 out of 26 ribs. I've since
replaced those 8 ribs and all 8 went fine in the second round.

I'm pretty sure the problem was in my milling. With the oak my
ribs had flat grain - if you looked at the end of the rib the grain
was horizontal. The ash had vertical grain - if you looked at the end
of the rib the grain was vertical.

After cutting the ribs to size and thinning the ends I soaked them for
about 4 days. Then when I was ready to bend them I steamed three at a
time (all that would fit in my steamer) for 18 minutes. They bent easilly
and look great.

Chris