The drum burnt out nicely and I started it up using a weber chimney starter as temporary fire basket (removed the plastic handle). (Sat it on a couple fire bricks.)
Started seasoning the bare metal on the outside with flax seed oil--I'll keep doing this until that oil / carbon is on really thick. (Gonna try doing this instead of painting it.)
Used my weber 22" kettle lid temporarily (hello Mushroom UDS). Vents wide open it approached 600 degrees F. The vents worked well when they got hot (maintained their shape)--I really think these 25 cent aluminum flashing vents are gonna work out well and last.
Gonna go buy some hardware to sit weber 17" charcoal grate on. There will be 3/4" gap around the outside edge but this should be fine. It's better than the lightweight 17.5" cooking grate that has these handles that get in the way. These thick charcoal grates will last a long time as cooking grates since the seasoning protects them.
18.5" WSM, Hasty-Bake Suburban, OTG 22.5", "Antonio" Bandera, Mini WSM