I am sorry and I know that I am going to be shot down for making these comments, but you are completely wrong by saying that using rudder will cause less drag than ailerons; in fact what you are saying will create a greater problem and chance for stalling. The best way to reduce drag is to make coordinated turns - use aileron to bank and small amounts of rudder in the same direction to counteract the adverse yaw caused by the ailerons. Trying to keep your aircraft level and ruddering it through the turn as you are suggesting is more commonly know as slipping in full size aircraft and creates large amounts of drag and loss of energy and airspeed, and is most probably one of the greatest causes of people spinning in and killing themselves while close to the ground in full size aircraft during emergency situations.

When conservation of energy is important as when you get a dead stick the following things are important: Maintain airspeed by keeping the nose of aircraft down, do not fly the aircraft at a speed just above the stall, in terms of energy conservation it is better to fly the aircraft to fast than to slow. Try to make as little turns as possible and when you have to turn try and make them as coordinated and shallow as possible. By shallow I mean long wide turn’s not flat ruddered turn. The last two things that one should be doing when trying to conserve energy is stretch the glide out by holding the nose up or ruddering the aircraft through a turn.

I know that I do not have much experience in RC aircraft but I have spent a fair amount of time in full size aircraft and although there may be a lot of things that RC aircraft can do that the full size ones can not do, they still have to follow the same laws of aerodynamics. Full size aircraft have a turn and slip indicator or a yaw string to ensure that a pilot always makes coordinated turns. (I have attached a image from wikipedia indicating the function of these aids in a engine out conditions)

Cheers
Pups