Tube rolling LTA MZ3


hi,
wondering if anybody has done any tube rolling with a LTA preamp? Just got one, my sickness immediately makes me wonder if I can make it even better! Anybody have ideas on weather the 12sn7 or 12at7 position would have the most influence on sound?  For me, (in my system, my ears) this pre is an upgrade from Pass Labs XP12. So much more dynamic and engaging.
thanks for any perspective, Ted
caglioti
I use NOS tall bottle 6085 tubes in place of the 12AT7’s. These are closer to a 12AU7 in specs but will work and sound great.
Ps. 4 6085s for both the AT and AU tubes. It’s important that all 4 tubes in the z10 use the same current
Have rolled NOS Mullard 6201's in place of the Genalex 12AT7s it shipped with. Smoother, less grainy but keeps the detail. Did not like any of the 12AU7's I tried including some NOS Mullards and Brimars. System seemed a bit lifeless.

Thanks to the suggestions here I got a pair of SIEMENS E80CC / 6085 for my MZ2.  Significant improvement over the GL’s that LTA provides.  Replaced the RCA 12sn7’s that LTA provided with a pair of GE’s and I think I prefer the RCA’s. Just got a pair of Sylvania 12sn7’s this morning.  Haven’t tried any of my VT-231’s yet.  Awaiting delivery of a pair of 1950’s Sylvania 12at7’s.