I've been using just under a gallon per hour brush hogging. I don't miss the 8N at all when it comes to fuel usage. Plus the diesel is much more safe to use.
Combined useage including field mowing, ditch digging, working arena, etc. in 35 hours I have used 12 gallons of diesel. Doing the math yields .343 gallons/hours. Most often I use the foot throttle unless mowing or excavating.
my fuel usage in my 3054 is maybe twice what you quote but i use the throttle lever and run the loader a lot lifting wood. i will try to keep a closer eye to give better numbers