no offense, but
You have all the experience you need. And you need to keep your two feet on the ground. If I understood correctly, you've paid 500 out of an eight hundred dollar job. So you theoretically have 300 dollars left. You may pay half that to rent the bucket truck (I didn't know you could rent those....that's scary). So by doing it yourself, you would be saving 150. You can easily do a lot more damage than that faster than you'd realize. I'd let someone with insurance do it. (And no, you're probably not covered to do this work yourself, unless you have some awesome insurance!).
Good luck and ask to see the business's proof of insurance.
love
nick