The foam slab will work fine on that small a plane. It might be a bit heavy for the .010, although they are pretty powerful.
The aerodynamics get pretty strange that small, so while it won't do anything awful it may not turn as tight or as well as a bigger plane.
It's got more drag than the same shape in a larger size.
Take a look at this thread:
stunthanger.com/smf/open-forum/testors-series-5000-049-engine-and-airplane-plan/msg405951/#msg405951
Bill Netzeband designed a very decent flying half A stunter from a couple sheets of 1/8in balsa. It was for the Testor's 049, which was a pretty handy engine.