Hey, Martin. Since the SAITO .30 is my all-time favorite engine, I have built and flown a number of different airplanes powered by them.
In general, any smaller plane designed for a 35 will work. My favorite is the Argus, a superb model that weighs around 42 ounces and flies with the best of them.
I recently put one on the Cardinette and it flew as close to perfect as I could want. That may well be the best plane for the 30 - time will tell.
If you like profiles, build the Sterling Mustang for the 30. It will also do well on a Flite Streak.
A few years back, I designed the Little Cherokee, patterned after my own personal aircraft. It's roughly Nobler size, has a quadruple taper dihedral wing and is a great flyer.
Bob Z.