Yes any barrel will work, I happen to live near wine country so hence the wine barrel.
To cut use a jig saw. I recommend screwing each stave in each ring before you cut it up.
The bung hole will have a 2"ish coper pipe that 90's down on the inside then 90's again on the floor. Haven't found a good control for the pipe yet but prolly a circle sheet metal plate or something with a screw in the top and rotates off set.
Since it's going to be electric with AMPS; air control is not nearly as important when using briquettes.
Still have that to do, and add the grates.