What should I expect to pay for a good used pair of autoformers?Is there an advantage to using the UTC 3619 over the original?I thought I read somewhere that the increments of attenuation are smaller than that of the T2A.Being that I am building Clones Of a Cornwall, I would like to use the simplest crossover first and progress from there .Would that be the "B" network? K-33,K-55,T-35.