Need Help with lighting set-up

I am shooting cars for the dealership I work for, we currently have 2 Alien Bee ab800's, one with a 48x72 softbox and the other with a 32x48 softbox. below is the set up and result picture. We are going to add a 3rd alien bee and am trying to figure out best placement and modifier if needed. The goal of the third light is to light the rear where the light is falling off(the orange flood lights are not used when shooting). Thanks in advance...

IMAGE LINK: http://www.flickr.com …pphotography/11​375480236/

IMAGE LINK: http://www.flickr.com …pphotography/11​375471645/

It looks like an expensive dealership, I hope you are getting a reasonable price for the photos. Studio car photography is big $$$

Here are heaps of good ideas

https://www.google.co.​nz …0CEkQsAQ&biw=11​52&bih=711

I saw a great tutorial done by the late Dean Collins where he shot a black sports car of some sort, I cant remember which and he made the point that when you shoot black cars the point is not to light the car, but to create the white highlights on the black paint where you want them. His solution was to basically make a giant sofbox by placing two lights behind a 8x10 ft scrim and hang the thing above the car. It gave brilliant highlights the curves of the car. I suspect you could do the same in that space using a pvc pipe to make the scrim frame and hanging it from the rafters. Regardless of your approach for a black car you probably want big light sources so the biggest softbox you can afford to deploy.

If you buy another light and softbox identical to the current light on the left and positioned on the same angle covering the back of the car, you will have a large soft light that is most similar to the very large custom softboxes used in pro studios. Cleaning up the paint line at the edge of the back wall will save you hours of Photoshop editing.

move the car farther to the left and it will pick up more reflected light from the left side wall.