Hi Buzzer,
I've seen some of Cully's work, but I don't read any of the books he as worked on. His style sits pretty squarely in the "old/new school" of animation artist I like i.e. David Johnson (aka DevilPig). Bart Sears is the same story, seen his work over the years with JL and Dark Knight.
Geoff Darrow on the other hand has been firmly in my "must list" I own most all of his books, own some of his originals, and had the pleasure of meeting and hanging out with him (probably more like stalking), Frank Miller and Mike Allred at Comic Con. All the detail I put into my models might be his "influence", however subconscious.
For this project I'd point to; Ron Cobb, Ashley Wood, Bill Barnes, Keith Weesner, Alex Toth, Francois Schuiten, and my good friend John Bell as influences. I certainly have more artist that I love, but those are the ones I point to with regards to Fuel & Fire.