Really no need to add flaps to a flat bottom winged aircraft. You already have plenty of lift.

I go with gaRCfield: choose a prop with 1" less pitch and 1" more diameter. Loose the speed brakes and tip extensions. That will slow your idle approach and allow better maneuvers. Speed will just give you more lift on a NexStar (or any flat bottomed wing). Spend the time to get a smooth low idle on the engine. This is a huge help in landing - you can land slower on low idle than dead-stick as the prop has a braking effect.

If you want to add the two-servo aileron option I would recommend you set them to raise together slightly. This decreases lift (the ailerons then function as spoilers) and will cause the model to approach at a steeper angle while the fuselage remains perpendicular to the ground. Whether flaps or spoilers you should only deploy them once the model is already slowed down on approach. Then throttle down and land. You should be using the throttle to control altitude as you bring her in on final.