Actually , different lengths , mine happens to kick 'em out in 4.5 , now my little Smoker may take 5 to 5.5hrs. or more .
One o the first things I urge a newbie to do is learn their Smokers inside out, all the quirks , losses , control , and leaking smoke holes . What I mean is that
you sit down a couple of days and play with it . Start a fire and see how long that last , then how much fuel you us in say an hour , or take it to a high temp. to
see how fast it goes to you chosen temp. , then back it off and check that . . .
The more you know our Smoker the more you can do with it , and the more you do the better you get . on and on and . . .
My big Smoker has a 20" FB and does better with 8"to 10" pieces . The little one is a reverse with a 16" round FB and takes the same size ...
Charcoal ? Same game . . . learn the hows , whats , whens , wheres , and Whys of the Smoker.
Hope I didn't lose you , I get long winded , but then , I like to hear myself talk .
Have fun and . . .