Steve, as others have mentioned, all things considering, you did really well.
In the future, if there's any chance of rain, I wouldn't use the grill for pizza. Water is the kiss of death for wood peels. Once they get wet, they start warping and won't perform as well. You could launch with metal, but that gets harder, especially with droplets of water on it.
I like the way you're bouncing IR from the IR burner down on the pizza using the shiny tray. You might even want to lift the tray a bit more at the rear and create an even sharper angle.
How big is your stone? Is there any chance that the pizzas are about the same size as the stone? If so, then that can make launching difficult. Even if your pizzas are smaller, I still think it's time to give yourself a little breathing space with a larger stone. A thicker stone should also go a long way in evening out the temps on later pizzas.
One thing that occurred to me recently is that it can be helpful to have a lip at the back of the stone to launch the pizza against. I do this with the wall of my oven, but you could probably created a similar lip using a 2" x 8" kiln post. A lip isn't essential, but, as you're mastering launching, it can be a nice training wheel.