Any Smoke Hollow 4-in-1 combo users?

I've been happily using my smoke hollow 4-in-1 combo grill as a smoker for about 2 years, after having used a Brinkman vertical water smoker for about 4 years.
Getting used to an offset smoker's difference from a vertical smoker took a bit, but I think I'm finally getting the hang of it after a half dozen successful smokes.

I've done some of the suggested mods to this smoker found online but I'm curious to know if there is anyone else here successfully using the smoker for long cooks with "thin blue smoke" success?

I'm also curious to know what your methods have been to achieve consistent cook fires for over 4 hours.

I've been using Royal Oak lump charcoal, minion method, and adding 3-4 chunks of smoking wood on top after the charcoal stabilizes with little to know smoke on its own. I've been filling the fire box about 2/3's full with charcoal, leaving the intake open about 1/4 of the way, and the chimney almost fully closed. This seems to get me about 3-4 hours before temps start to fall and I have to reload the box with another pre-lit chimney of charcoal.

Anyone else with this smoker care to share their method/success with it for smoking?

Thanks in advance!