I guarantee NONE of those things you mentioned is perfect, maybe good, possibly excellent, but still nowhere near to the way any 6.00 vaulter would be able to do them...
But anyway, it sounds like that pole is just way too big for you... unless you're just trying to stiff pole, and if that's the case that's a perfect pole. What's your mid at for your grip? I'd take a guess you're holding at least a foot and a half down on the pole, putting you at about 6.5ish meters per second at take-off, with a take-off mark of around 9'8'', am I correct?
I am increasingly seeing an obsession of kids I vault with about breaking in their bottom arm. I see it as a pointless thing to try to focus on during a vault, even during a drill. They're just like, "Oh, all I need to do is break in, and then I can get inverted..." Right, like THAT'S what's keeping them from getting inverted...
If you swing correctly, you'll be in position to become completely inverted. 99% of the time, the swing is the problem with inversion, unless it had something to do with a phase even before that...
You said that you were confident in your run and plant, but what about your swing? If your run and plant ARE perfect (again I guarantee that they are not, but whatever, let's just say hypothetically if they were perfect,) then the next thing is the swing. I know what you're going through, because I have the same issue. I no heighted today, coming in at 10'6'', because, among a few other major issues like fatigue from being an idiot yesterday and practicing today for an hour or so, (we had a meet at practice to count for the pitless school our next meet is at on Monday, so...) I consistently drop my drive knee and do a crunch/sit-up through the chord of the pole instead of driving it high and hitting the chord long. You need a highbar, just like I do. I would KILL for just an hour or so on a highbar. If you get one, I'm positive that within a few days of practice on it, you'll be going at LEAST 12 feet, if not more. Good luck, I hope I didn't sound too ticked off, sorry if I did...