I've recently just retubed my Ph3 after 9 yrs(standard tubes were sovteks 6922. The new ones that i got from ARC are EH)Got the low output zyx bloom first to see if i had adequate gain in my phono section before i took the plunge for the 4D.
Comparing the old ARC ph3 tubes to the new ones, In My system the New tubes obviously breathed new life into the sound but i would say the most that i gained in the volume pot was about two clicks at the most. Can't say if this would be the same in your case.
hope this helps,