BigRat,
Ahh, didn't realize you were focusing on the specific double-immel move, my mistake for not reading more clearly. If you both fly that aggressively, then it comes down to whoever rides the edge of the envelope better. From what you've said about all that flap/throttle work, it sounds like you already knew this (whether directly or instinctively) and are getting much better. I just would not fly the 109 that aggressively Co-E if the merge happens around 200-300 mph. I would bide my time and go aggressive when I have built up the advantage.
Personally however, I visualize ACM as a fluid process rather than a series of "moves". I know the "moves" and often use set piece tactics, but overall, I am constantly evaluating the situation and picking a fluid way to deal with it. I probably would never even think about trying to find a counter to something so specific as a double-immel.
I'm always asking myself "How's my E state compared to him? What about any angle advantage? What's my speed? How could I get behind him best? Do I need to put up a guns defense right now?"
In your case, all the advice given by others applies to how I would fly. I would begin by doing a lazy low-G pullup and evaluate what the 109 wants to do. If I see he got greedy and is already trying to get his guns on me after the first pass, I'd keep on climbing, maybe pulling over the top and rolling level to go shallow, or maybe going into a flat turn at the top of the climb. With the E he blew trying to get guns-on, the 109 won't be able to follow you up immediately. That goes for a double-immel as well, even if the first one was somewhat lazy/conservative. An aggressive second-immel would be too early to have built up a good advantage for the 109 to get a good guns solution.
At that point, I'd either wait for him to stall out trying to climb up, or (if he refuses to try to climb up to you) wait for the right positioning to drop down on his 6 for the kill.
If at any point he DOES get guns on, I'd roll to point my wingtip at him to give him the hardest shot possible (90 degree deflection, no planform) and keep trying to make him blow energy.
The reason I don't recommend engaging Co-E A-D hog vs 109G2 and above is that as the Hog, you are relying on your opponent making a mistake and blowing his energy by flying too aggressively. It's been done before, and not unlikely. I probably have been such a sucker before myself. Nonetheless, this means the Hog is not in control of the situation. With its superior climb rate/energy building characteristics, the 109 can dictate the terms of the fight if he so choses.
In fact, if we are talking about sucker moves... try this as a counter: let him immel once and get your six. You pretend to go up with him, but as you see him pulling around, you reverse your climb and go for the deck (assuming we have some space to accelerate to around 500 mph). If the 109 follows you, he should be dead meat
. He'll either lawndart or blow a lot of energy/positioning trying to recover from the dive.
Re: the 4 hog
. Yeah... somethin like that. Still doesn't climb like a K-4 though
, but I wish the K-4 had guns which were as easy to use as the 4 Hog.