Hey Bill! Actually, I originally made 2 center ribs by the rather crude method of building everything else on the wing and then gluing a 1/8" balsa sheet at the inner end (offset to allow for dihedral), a ruler laid across the line of ribs to trace the "proper" shape of the center rib, and then cut it out. Gotta tell ya, it was even more interesting recreating all that once it was smashed. Anyway, once the rib was cut and the wings were together I hollowed out enough of the pair of ribs to fit my 2 servos (side-by-side) for the ailerons. When I re-built the center I used just one 3/16" rib, inserted after the wings were together again, and put the servos on each side of it. I'd love to ask Maxey why he designed it without a center rib, but I'm pretty sure it's a bit late for that (LOL).
I definitely recommend 2 servos, however you do it.
Hm, retracts would be rather interesting on this ship - there's plenty of room under the fuel tank for the nose wheel, for sure. I'm positive the wings could take them too - more than enough strength there.
One thing Heggen did, and I copied, was to increase the aileron size (front to back). Plans call for .75" - probably because of the radios back then, I went with 1.25". I think Heggen did pretty much the same. Hopefully, he'll pop back in here too.
Like I said earlier, the 1967 Stratus is perfectly happy with turns using only rudder. My 1967 Sr Falcon performs almost as well, but I dropped the dihedral on that to near zero (.75") when I built it and she doesn't come out as level, as easy, as the Stratus on just rudder. My only other 1967-era plane is a DeBolt Champ which is 3-channel. I've got a sneaking feeling, though, that many of the planes of that era might be fully flyable on just 3 channels.
Just asking - do you have Heggens' rib drawings? Just for giggles, I'll try to attach them as a MS .doc to this. Shoot, too large a file. Might be able to e-mail them though.