Odyssey 31 Battery Mount Options

Finally got my 31 battery in from 4wp, looking for the best ways to get that sucker in there.
The weight concerns me, and I've heard from others that it will not support or secure it down all the way.

I know Pelfrey used to make a box, and Rago makes one now - but is a $250+ battery cage really necessary?

If you have some alternatives, would love to see them and hear how you made it work.

 

Hey 254runner, what did you end up using - any photos?