The early and later plans show only the diamond airfoil and yes the wing tips are reversable.  Black Hawk Models currently produces a laser cut kit for $45.00 and a double kit for $80.00.

Look under AC models in their catalog
www.blackhawkmodels.com

Larry

High performance flyers put the big end of the tips forward for quicker turning.
Beginners put he big end in back for more stability.

Kits a bit awkward as im one of these forigners from the stone age . I dont even have , or want , a phone .

Thanks for the tip on the tips , Brother had a OS 30 one I flew a few times when I was about 12 . can remeber doing a few loops and the like .
The thing lived for a while .Launching for another cowboy , he stepped back hard BEFORE Id tossed it.Hand on inside wing.The scar on the
little fingers almost gone now, 3 good chews , one near to the bone , So I dont put a hand on the front of the inside wing for some reason.

Over 200 sheets of good wood in the shed now , and this is one ive been keen to do for ten years or so, thanks for the advice ,