I used 7DJ8s in my Herron preamp and enjoyed the exact same benefits as you. I would suggest buying multiple sets as they didn’t last more than 18 months in that application. Totally worth it though. Love your gear!
If you have a Steelhead-
I have been a very happy original owner of a Manley Steelhead for five years. All this time I had the stock tubes. I recently changed the tubes out to vintage 7044's which are just rectifiers in the Steelhead and then Matsushita / National PCC88 / 7DJ8's for the output tubes. I am posting because the upward. change in palpability and engagement is incredible. So if you happen to have a Steelhead... See my system if you care. My favored cartridge right now is a Lyra Etna Lambda on my hot-rodded Garrard 301 with Reed 3P on a Layers of Beauty plinth.