Going to the vertical is great because you can maneuver and turn into another vector without losing very much net E. Let's say the spit is turning hard and I'm not gonna be able to get inside his turn, I have several choices at this point. I can lag roll, keep my E up reset for another run. This allows me to keep up my E make him burn his at an exceptional rate (cause he's still pulling on that stick to come around). Hopefully, you'll be able to get inside his turn the second time around. Remember too that the closer you are to him, the more are gonna have to pull to get inside his turn. The further away, your turn distance is way shorter than his. With him showing that big profile of his plane, a D400 or D300 shot should not be hard.
The other vertical maneuver I often do is turning in the vertical. This move is simply an exaggerated lag roll. Unlike a normal lag roll where I make a moderate sized roll, In this move, I pull straight up (90 degrees) and stay there until I get down to about 200 mph. There, roll to point my lift vector to where I want to pull then I pull over in the direction he's going. In this case, I'm turning by rolling with ailerons vs. elevators. Of course I'm gonna have to use some elevators to pull over but the net E you lose doing this is much less than if you simply just try and follow him through a flat turn. Again, the point here is to make him burn E reacting to you while you bank yours. For every maneuver, you want to be stingy on E. This is sounds like a very conservative way to fight but remember that you never know who's in that Spit.
Lastly, if the spit you encounter starts to maneuver in the vertical with you, watch out! The moves I just explained are moves I use in the Pony and 38 and most of the time, it works well for me. Like I said, I don't fly the Corsair much but I would wager it would work there too with the F4's great zoom climb, roll rate and uber flaps.
I only watch and save clips of me getting shot down (which is a lot) and I've learned one over all lesson. Every time I loose a fight, it was because I made a mistake. The fight to win or lose is all up to me, not my opponent. From the very start of the fight to the final shot, to win, you must make fewer mistakes than your opponent. You must judge E better than him, you must be more accurate. You must know when to take the shot vs. laying off for better position. Even the ubiquitous HO is subject to this philosophy as well. 100% of the times I have been HO was because I allowed myself to be HO'd. I think analyzing your fights with this philosophy in mind will make your lessons learned more impactful.
Good luck.