Shuguang KT88Z v.s. EL37 Mullards v.s. KT88/66 GEC

I am still undecided however I am going to buy some Shuguang KT88Z anniversary, GEC KT88, GEC KT66 or EL37 Mullards. Its almost impossible to find Fat bottle EL37, but even the usual ones are so expensive that I am wondering why is that. Because they are very rare or because they are sound so good/the best. Financially the winners are Shuguang KT88Z tubes. Above that, they are new and you can get enough of them at the moment, if need it of course. This is very hard for me, cos I never tried any other KT88 or above mentioned to compare with my stock reissue Genalex. So far have tried 6550 Tung Sols Grey & Black plated plus 6550 Sylvanias. I didn't like Sylvanias that much, but Tung Sols were very good, but still not that good I want. Tung Sols have better detail, airiness and bass texture, but the mids were bit cold/distand. They become better after I roll some pre tubes, all Mullards/Brimars, but still lacking. That's why I need something else, where Shuguang been on top of my list, however just wonder how would they do v.s. EL37 Mullards or GEC guys. I really don't want to be "surprised" to find out that Shuguang KT88Z sounds like 6550 Tung Sols Black plated, which are great, but not enough for me.
So, the bottom line, what is the best solution. I do like detail and airiness, but need the bass and silky/involving mids. Which one can fit the bill at best?

My amp is PRIMALUNA PROLOGUE TWO.

Many thanks,

Sergei.