That sure is the long way around to get to this point but I believe you will find this a very rewarding experience and when it's done, there is nothing like popping open the hatch, showing the goods and saying "I did this myself"
Good luck with it.
Oh and just my first impression from what the installer did: Easy on the MDF!! That sheeite adds a lot of weight. Your not exactly working on a truck, it's a ZO6!