Thanks for the reply Aardvark! 

I agree with a lot of what you're saying, I haven't gotten to the straps yet (doing that today) or the grips for holding the beasty.  I'm treating this like a MK-I flamethrower, I.e. a prototype.   The guy making it has just cobbled it together and hasn't worked on the ergonomics yet.  I've got some batteries to attach to kind of "show" those rings are the electric ignighter (like you guessed) along with the mixer/flow valve that goes on the back. 

I agree a big giant nut will look great for the hose connections.  I think the MK-II will look more like a real flamethrower but going off of no references (but the ones in my head) not so bad eh? :)

Oh!  As for holding it I was thinking it might be held like a Smartgun from Aliens.  You know big grips over the barrel allowing it to hand down and aim with a grip trigger on the rear and the front grip just for support.  I want it to have the feel of being too big and unwieldy to be a production model you know?  :)

Thanks again for the feedback!