Primaluna dialogue premium HP tube rolling suggestions to reduce brightness

I have had the dialogue premium hp for about 6 months now, using naim preamp and proac tablette anniversary speakers.  I have been noticing some brightness in the high end, and am wondering is I might be able to switch out the tubes to cool it down a bit.  

I am running the stock el34 and 12au7. As this is the hp with 8 power tubes, I would rather not switch the el34 for financial reasons, so does anyone have recommendation to change the 12au7 tubes.  

I also think the the proacs are contributing to the brightness, but would rather not go speaker shopping again, but have not eliminated that option if you have some ideas