The battery bay is perfectly shaped to accept a double stick of 7-8 = 14-16 GP-3300 sized cells. It's made out of FG and has the required flattened oval shape. Perfect for sub-c Ni-xx cells. Too bad nobody really cares
That FG tube needs to come out. But boy did they secure it well, between intake & belly . When it's out, two sticks of Kok 3200's (3S+3S=6S) will be a perfect fit, and the CG should come out ok too (I re-calculated it).
So, to make a long story short, I need to dremel two long cuts under the belly and get that FG battery tube out. After that, the Kok's will fit perfectly (they are about as thick as a GP cell). Then it'll land right on the Kokams