I don't know anything about the Bryon Glasair, but I can tell you that a 30cc engine is going to be panting hard most of the time if it has to drag around an air frame that heavy. Not likely going to have much reserve power at all.
I'd be looking at the next size up, 50+cc's. If you're buying an engine for it anyway, they aren't that much more. Then, if the budget could swing it, a twin would probably work really well in a plane like that.