What's a Henway?, about 2.5 pounds. I'm not sure why you are going to the effort to fiberglass the fuselage, elevators, and flaps. You risk excessive weight buildup and at this point in your learning curve it really isn't necessary. Silkspan and dope should work fine for these components.
If as I assumethe components include the engine, tank and wheels, that is a good weight. Wing tip weight will add another ounce. From here, a dope finish should not add more than 4 to 5 ounces which keeps the airplane below 44 ounces easy. For your purposes it will fly fine at that weight. Mine all up is 39 ounces which is light but I turned it into a "D" model which removed some wood weight. It is a very good flying model. Silkspan and dope overall.