Jason,

The batts I think you ordered (http://www.hobbyking.com/hobbyking/s...dProduct=10096) have the following dimensions - 147 x 49 x 34mm

The tray is only 143mm long so I think you'll have to do some modifying or use that AE sponsorship deal if you decided to renew and get this Reedy pack (http://www.teamassociated.com/reedy/parts/details/626/). I'm pretty sure this is the pack that I'm going to use.