I'm doin something similar to that right now. Except I'm using two .68 carbines and there will only be one grip inbetween the guns so you can actually hold it. I'm putting a firestorm crank on it, but I shaved down the little tab so I need to find/fab. a new one. Headaches...
Back to topic, looks good, but I agree, where would you hold it? That and the big space between the guns is kinda awkward and ugly.
BTW, anyone know where I could find that firestorm tab thingy since it looks like the company went under?