im about to buy a sooteater...heres my questions...i think my ss liner is 6 inches...do i measure around or across to make sure?....also do u all use a vac with the sooteater?..anything special with the vac?..and how do i measure how long my chimney is?...so i know if i need extra rods....these may be dumb questions, but sure would help a hillbilly out...thanks in advance