The credit goes to ratdawg, he built it for me as I don't have the welding skills, even though I'm a contractor.
For my seasoning burn I put 1/2 chimney of lit Kingsford over 1 1/2 chimney's of unlit and 3 fist sized chunks of hickory at 3 pm.
Locked it in at 235 with ease, and played with the intake and got it up to 275 and down to 200 within half an hour.
Still holding at 235 at midnight, tapped the basket to drop the ash and went to bed. Got up at 6 am and it was still holding at 200, 15 hours later.
Had to go to work so I don't know how much longer it would have held, but I wouldn't hesitate to do an overnight cook on it.
When I smoked the butt I used the same amount of fuel for about 5 1/2 hours, then closed it up and there looks to be about 75% of the coals left over for the next time.