Its totally feasible dude. What would Otomo do james? Craig Thompson and Paul Pope both seem to be going balls to the wall. I think you should try grand at least once.
it's important for new creators to not go grand at their first outing. Otomo did Akira because he had ten years of experience on short stories and it's the same with Paul Pope. Doing your opus right off the bat is almost always a really, really, really bad idea.
Great concepts, amazing characters!
break it down into "chapters"/ segments and do one part at a time. please? maybe?