Hi ken,....It is difficult to advise you on actual numbers, because not knowing your intended use of the model it poses too many variables. What you are talking about is called Aspect Ratio!! In a power model this generally between 7 and 15 to 1. In your case ,at the lower ratio ie; 47 divided by 7 is around 7 inches. Wing thickness should be from 8 to i2% of the chord. Nose moment distance from wing leading edge to nose 1.75 chords....Tail moment is distance from the trailing edge of the wing to the leading edge of the stabilizer ie;is 2.5 to 3.5 chords. 47 inch span by 7 inch chord is 329 sq inch is 2.41 sq feet.multiplied by flying weight is wing loading...... around 12 to 16 ozs/sq foot. Hope this helps.
Brian C
Brian C