Loger, I always assumed that you burned a lot of hardwood. I certainly did too but I also included a significant portion of softwoods as well. For many years I was using a Franklin fireplace which is practically the opposite of a modern sealed unit with 6 or 7" insulated flue. I never had any oily or sticky or thick buildup. I only cleaned every few years. The closed modern unit didn't respond differently for me, but I was burning a lot of softwoods then to use them up before I moved.

My understanding was that the main problem came from slow controlled burning. Since I see your 14" pipe, I assume you are burning with an old fashioned stove, even if more efficient than my Franklin. If it is not tightly sealed, I would expect your burn to be hot enough to prevent serious buildup. But It might be worth googling air tight stoves and creosote before you through caution to the winds.

The Chimney and Box sweep was no challenge except chimney to box trips (that challenge my legs).

1. I Swept the 6' of chimney with a stiff 18" broom head clamped parallel to 2" PVC (a 14" dia pipe brush in the future).

2. A short handle broom works well in the box with a box fan pulling up the chimney.

3. It's always the thought and mess vs the actual work that I hope to reduce yearly.

4. What is the best source of getting rid of the approx gal of soot (reg trash sealed)?

Note: I'm burning 90% Oak and Pecan with very little softwood as starters if pecan is not considered soft. I keep the damper 3/4th closed (just to eliminate int smoke) or all the heat goes up the 14" pipe IMO. The 14" pipe was due to it being a Double Faced Fireplace. I added a steel back with a steel 6" back-log, two, 2" stainless grate tubes connected and 7, 2" stainless tubes above the fire, all open to the back side. With the plate glass doors closed at night and ducted combustion air into the box, we get safe heat and good coals the next morning.

I let the Defiant burn wide open for about 20 minutes a week. But this is in a brick chimney with a flue liner. I do have a set of brushes and poles. I havent used them in ages. Makes a mess.