Assuming same planes and equal energy state I would say the one who finds the best angles will win.
I know it aint a straight answer to your question but Id say its what will separate the two. Simply because if one pilot can find the angles and the other cant the first will get on the seconds six before the energy state becomes critical.
If both work the angles equaly well they will basicly consume the same ammount of E and then it will be about who makes the first mistake. In a very close duel one common mistake is shooting at the wrong time. Shooting in the wrong time can be extreamly lethal as you mostlikely pull your stick a little bit too much and loose position. In a close fight any pull on the stick for a shot will make you loose position and bleed that little bit of E that will decide the fight.
If you view films of the really good pilots dueling the never ever ever move their nose while when they shoot. They sometimes do take a chance and fire a shot that is a very low percentage shot but they never ever pull the stick doing so. Better to miss and not loose position and E.
Also in your question you say drop flaps and turn. I assume you mean manouver and not actually turn as flat turn.
You should always use your flaps accordingly to your planes ability and need.
How flaps are used and when very much depends on the plane you are in. But for example in the F6F and the P47 Im more or less constantly working the flaps when in combat.
But as said it will come down to who finds the angles. Finding angles is something else that one really just needs to practice over and over.
Personally I would divide the pilots in the MA into the following cathegories.
*The totall dweeb, goes for HO shots, doesnt know how to avoid them and always does a flat turn after merge.
*Avg pilot, still HOes but does go vertical after merge, no clue about how to find angles.
*Above avg pilot, avoids HO more then takes it, goes vertical after merge, can find angles, cant use flaps and rudder correctly.
*Good piliot, avoids HOs, goes vertical after merge, can find angles, can use flaps and rudder and knows his ACMs pretty well.
*Ace pilot fantastic in all aspects.
Basicly learn how to merge and do vertical opening manouver manouver and you will be able to beat 50% of the MA, learn to work angles and you will beat 75%, learn to use flaps and rudder in your ACMs and you will beat 90% of the MA. That level of skill can be reached relativly quickly. Beating the top 10%, that will take years.
Tex