What I need to work on for pole vault.

So I am on the track team at North Central College. My event is the pole vault and I love it but I have a lot to work on. My current PR is 13'3" which may sound high to some people but I believe I have a lot more in me if I can fix my take-off. To put it into definition, the "take-off" is the transition from the run down the runway to getting into the air. Compared to the other aspects of my vault, this definitely needs the most work. What happens to me is my plant is usually late, which means I get the pole above my head late, and I don't have a straight trail leg. I've been working with Coach Fitts to try to confront these issues. 

For my late plant, he's having me do these drills off the pit with the pole where I only hold it in one hand and let it fall as I count out my strides on my run. Hopefully if I get good enough, the pole will hit the ground at the same moment my top arm is holding the pole straight above my head. If I continue to have a late plant then it could lead to my top end of the vault to being unpredictable, so it's super important to get it down early. 

For my trail leg, I have to keep it straight after jumping up at take-off. Really, this is just a bad habit more than it is anything else. A drill that I am doing to help burn it into my muscle memory is hanging from a high bar like I'm planting a pole vault pole and swinging my take-off leg while keeping it straight. Usually it gets bent, and it results in the pole receiving less energy. The pole needs to receive more energy because then it will bend more, and then I would get flung higher to jump higher bars.