@laaudionut I haven’t tried the Shuguang Treasure 6SL7s yet, but I have tried the PsVane CV-181 (6SN7) TII which are very similar, if not identical to the ’guang Treasure CV-181. I can assuredly state that the Linlai Elite 6SN7s blow the TII 6SN7 Treasures out of the water. I don’t know if the SL7s will match up the same, but my gut says the Linlai’s are superior tubes. You can purchase Linlai from Grant Fidelity in Canada, or for quite a bit less from a reputable seller on eBay "kt88_6550" whom I’ve purchased from more than a few times with excellent service.
Aric