Jkstone, If my recollection serves, memory not withstanding, my firebox is about 52 inches in circumference so yours should be fine.
With regards to your UDS customization - I think it's a great/clever idea but like some others have stated, isn't at all necessary based on my albeit limited experience. BUt I shall still share it hehe.
Like I said my, firebox is roughly 14-15in diameter, whatever the weber replacement charcoal grate is... and it's 8 inches high. I have a 3 in air gap between the bottom of the firebox and the ash catcher. I've loaded it with as little as 7 lbs of Stubbs or Royal Oak Brickettes which fill about to the middle of the box and then poured a 14- to 1/3 full chimney of lit charcoal in the middle (I use a generic chimney which is smaller than the weber genuine one). I have never run out of charcoal. I have always had coals left over. I haven't had a cook last less than 10 hours. I'm fully confident I have the capacity to run 20 hours before considering adding charcoal. So that's my experience. Hope it helps. Still, looking good mod there and hope you get some great cooks outta there!!!
With regards to your UDS customization - I think it's a great/clever idea but like some others have stated, isn't at all necessary based on my albeit limited experience. BUt I shall still share it hehe.
Like I said my, firebox is roughly 14-15in diameter, whatever the weber replacement charcoal grate is... and it's 8 inches high. I have a 3 in air gap between the bottom of the firebox and the ash catcher. I've loaded it with as little as 7 lbs of Stubbs or Royal Oak Brickettes which fill about to the middle of the box and then poured a 14- to 1/3 full chimney of lit charcoal in the middle (I use a generic chimney which is smaller than the weber genuine one). I have never run out of charcoal. I have always had coals left over. I haven't had a cook last less than 10 hours. I'm fully confident I have the capacity to run 20 hours before considering adding charcoal. So that's my experience. Hope it helps. Still, looking good mod there and hope you get some great cooks outta there!!!