I mounted the tray at an angle because I was trying to get as much weight as close to the center of the chassis as possible. It doesn't come with any mounting hardware or instructions. I got it mounted using my own ingenuity. I hope it stays put once this thing starts taking a beating.
I bought the RC Product Designs kit back on the 5th of December. I have yet to receive my kit. Although I have gotten a couple of emails from Dan apologizing for the delay.

He says I should have the new tray by mid March. I got tired of waiting on him and bought the RC monster mount and tray. Which I will run happily. Even after I finally get Dans kit I may only use his battery tray. We'll see.
Thanks Monster Mike for the quick service.