Two by Four: Lit 05:41:42, goes out 7:47:24, total 2 hours, 5 minutes, 42 seconds.
Charcoal: Lit 07:50:12, goes out 8:05:00, burn time 14 minutes 48 seconds.
2 charcoals: Lit 8:05:30, goes out 08:15:00 burn time 9 minutes, 30 seconds.
1 charcoal in, 2 in the source: lit 08:15:26, goes out 8:25:00, burn time 9 minutes 34 seconds.
So yeah, charcoal doesn’t burn for long at all and seems to have the same issue.
And currently it looks like two by fours are significantly better than heavy sticks.