What I find interesting about tube rolling is that the effect, in my experience, is often bigger than the effects of changing power cords, feet etc.Yes yes yes yes yes!
So happy you like the RCA 12H7. It is a special tube. I never heard a tele 12au7. But I tried many other 12au7's and 7602 and the RCA is the king for me.
Once you get your system tuned with tube rolling, then cable differences start to make a big difference. Start with IC from pre to amp, then put in a nice conditioner like the Running Springs. And then a top power cord into that. Then power cords for preamp and and IC from sources to pre. Finish with power cords to amp and finally speaker cables. This is the order for which things made the most difference as I did all the updates.