The Fox .35 is kind of a "White Elephant". All it's good for is C/L, it needs fuel with all castor oil, it needs a lengthy break in and possibly an experienced hand. For less money, get an OS .25 RC engine, swap in a C/L venturi that you can buy seperately and you will have an engine that runs better than the Fox on ordinary fuel and also be ready to go in an RC plane if the need arises.
I would look at any C/L plane above .049-.061 powered as being a secondary trainer. The ground comes up mighty quick.