I don't know if adding $4500 worthy of massless tweeters will do you good, but here are some tone controls, I found very effective. Please don't throw things at me for this. I had a bright analytical system with tubes and Focal Electra speakers. I introduced Cardas ICs Golden somethings and it was like heaven. Second I highly recommend rolling every tube I had KT-90s in a small amp and found them bright as well, use GL reissue KT77s. Get every small signal tube that is Chinese or old Russian out. Replace with NOS if possible or GL reissue (yes I know they are Russian but they are mellow). Get the cables I kid you not they are now NOS or used but that makes them cheaper.