Dan,if you want some voicing options,equal to the difference in sound between two arms,get some different brands,but high quality NOS tubes.This will definitely give you a bang,for the buck.Unfortunately it'll probably cost as much as the additional arm,with the prices for good NOS being absurd,these days!!In my phono-stage I currently have KILLER Siemens CCa's.I,also have two different sets of superb Ediswan phono tubes(as back-ups).Different characteristics with the Ediswans having a bit more swagger,but the CCa's(mine are lower noise than almost any previously available)that I have are like listening to GOD's phono section.Only a fellow hobbyist,like you could understand!
Best regards!