First here is a layout of a 6 or 8 panel cape I found on BOTB, thanks to batcavehq.com...
And a link to a thread of a very accurate Panther design...
Brotherhood Of The Bat :: BOTB Main Forum :: MRX Panther- Cape ~ Runboard
You can see in this pic from that thread that it clearly shows 6 panels and looks just right on the full suit...doesn't hang TOO far around as you don't want that on the Panther look....
Unless maybe I'm completely wrong but I have built 2 Panther suits in the past and they each used 6 panels. I had an 8 panel Artsee at one point and it wrapped around too far. I used that for my Returns style. Then again, maybe it all depends on the width of the panels?