Power Tubes Quicksilver Mid Mino


Just picked up a up Quicksilver Mid Mono along with 6 Mullard XF1 EL34’s. The tubestest surprisingly strong, but I want to extend thier life as long as possible and also try a different Tube Type. Any comments on the Gold Lion KT77 or KT66’s in the mid monos?  I’m using a fairly efficient pair of Audio Note AN/Es, so I don’t think I need KT88’s or KT120’s.  I’m running my exogal DAC striaghf into the amps.  Great combo.  Haven’t felt the need for an active pre.  Thanks.
markhh2
I love my Mid Monos...   KT66 sound great , as do KT88.   I am running Mullard repops in them now and they sound great too....    so when I need a change of pace I will swap types .  Overall I think I prefer Gold Lion KT66 but the quad I had was getting tired so down the road I will get another quad.   I would love to hear from anyone that has used the new 7581a tubes in these amps...
I have had speakers from 87 dB sens to 99 dB and these amps had plenty of power .... they are great amps.
I liked Gold Lion KT88s in my mid monos.They rolled off the highs just a bit but the mids and bass were excellent.
@oddiofyl I use new Tung Sol 7581A in my EICO monoblocs. Awesome. Great bass and clear clean highs. Search for my post on these in another thread.