6SN7 and 6SL7 tubes recomendations (Cayin A88T integrated)

Hi everyone,

my integrated Cayin A88T uses KT88 as power tubes, and 6SN7 and 6SL7 as preamp tubes. I would like to upgrade the tubes, what would be the best options with new tubes (not NOS)?

It seems that 6SN7 can be substitued by cv181, but their are many nrands an models. The same for 6SL7, many option (Shuguang, Psvane, Sofia Electric...).

I'm currently using TungSol new tubes. Already have some NOS (RCA, Silvania), didn't like them (less detailed, not so open sound stage...).

Thank you.