Which NOS tubes on my ASL 1009 for more warmth?

I'm lookin to replace the stock el34 and 12au7 tubes on my ASL 1009's. I want some version of the old Mullard el34, not sure how far to go with these...and the 12au7's I have no idea what to use here. My system is Wadia 302 direct to the amps (and that is probably why I'm lookin for more warm sound) and Guarneri Homage speakers, TG audio ic and speaker cables. TIA.