King: Are these supposed to be exact copies of the Mullard CV-181's?
I don't think so. Checkout the end of excerpt from Grant Fidelity website below.
CV181-Z (pair)This tube is a true 6SN7 equivalent and you can use it in place of 6SN7 tubes of various brands. It has identical specification as RCA 6SN7. Do not use it to replace NOS CV181 tube.
King, question: when tube rolling the Transporter, was this eval done with the LSA in the chair or your tubed pre-amp?
Active preamp ... LSA is only use for background music.