A heat diffuser is a must with most smokers but so is a heat sink. I am old school so I use a water pan but some use sand.
BTW: I agree that you got a good deal on a great old school vertical smoker. Spend the time and get all the rust off. Rust is your enemy. Do the mods and fire that bad boy up. You're gonna love it!!
Weber Platinum Kettle, Weber OTS, Meco square grill, ECB, a WSM, a cool fold up camping grill, a Blackstone flat top camping stove, The MOAB, and now the proud owner of a YS640, MOINK.
Smoke on Brother KC
Father of the Fatty (the name) 4/20/04 on the BBQ Brethren with inspiration from Brother parrothead.