4-40 is overkill for a 40 size model. But like Teebox says if weight is not a concern leave it alone. Also be careful with metal clevises especially on the thtottle. Metal to metal vibration is very bad and causes RF interference. I don't like to use metal clevises even on the control surfaces unless I have 4-40 locking nuts as well. Ony do that on the bigger planes though.