"Adults usually grow no more than 2m, but some have been recorded at 2.5m. There was however, one exception, one M.s. Variegata was recorded at 280cm at four years old."
From the incredible obscure website Wikipedia.
Sorry, feeling a bit testy today. As long as you don't chop the tail off your snake, I've no cause to complain.
Edit: Oops, you were asking for thickness, not length. Even less reason for my snark. Sorry!