The angle you use to go up in your zoom depends on too many variables for auto-speed to be a good choice, at least IMO. If you are VERY fast, and your low targets can't possibly touch you, I suppose it would be fine then. In that case you're just turning energy into altitude without any immediate "plans".
In a situation where I'm zooming to maintain and improve my position over a specific opponent, I think any of the "auto" options would be a significant handicap. I'm way too busy looking out of the back of the plane, rolling to fine tune my view or to align myself to reverse back down onto him. I'm also adjusting my climb angle to place me in the best position to reverse. A lot of that depends on our relative speeds, and what he's doing to make things easier or more difficult for me. Do I need a bit more height, or a few more seconds? If so I'll stretch it upward a bit more. Do I need to reverse quickly in order to keep pressure on him, or take my shot before he can recover from his stall? If so I'll reverse without ever reaching the zoom height I was capable of.
The zoom angle and height need to be adjusted for every situation you find yourself in. I generally PREFER to go as vertical as possible, to get every bit of height I can get, but that isn't always possible or preferable. Too steep might get you killed in a particular fight, or too shallow may have the same result. It's really going to depend on your immediate needs, based on your opponents position, E-state, and "ability".
Reversing at the top varies for the same reasons. Generally, I don't hammerhead at all. My normal reverse will go into effect about 125mph, by simply applying more up elevator and two notches of flaps. Think of an upside down raindrop, and that's my normal flightpath as seen from the side. The thickness or thinness of the drop will vary depending on my speed and "plans". Against planes like the Hurri's, I'll "loiter" a bit while inverted, since they seem to like coming straight up at me in an HO type attempt when they see me top out. This would make for a pretty fat raindrop. By loitering I give them a chance to come up and stall as I come down to hit them. I generally only "loiter" 2-4 seconds. This lets me shoot them as their nose drops, denying them a gun solution. Again, it varies with each fight. My goal in a roping type manuever is to reverse onto them while they are about D800, very slow, and unable to catch me. I want my reversal timed so that as they stall and flop, I'm on my way down, picking up some speed through D600, finalizing my aim at D400, and shooting them in the cockpit at D200. I don't wait for them too stall before I reverse, because I want to be shooting them at that point. If I wait for them to stall, by the time I've reversed they have as well, and now it's a tailchase. Important note- I pull my flaps back up BEFORE I'm fully nose-down on a reversal. They're only deployed while they help me get over the top, and are retracted before they start hurting my dive. I NEVER let them auto-retract. Flaps are never "neutral" in effect IMO. They're either helping you or hindering you. If they're beneficial, leave 'em down, if not, then bring them up. Don't let them suck your E advantage away by dropping them and ignoring them...
A spiral at the top? Yup, quite often. Normally I do that when I need to stay high just a touch longer to put them in the position I described above. I'll also use it if the guy is a bit too close, and shooting at me. If he pulls lead for the shot while I spiral he'll usually stall out so I can pounce on him.
This zooming and diving attack is the same attack I use on bombers, just adjusted a bit for my speed vs theirs, etc... I'lls ee if I can post a few films.
MtnMan