im on the same situation kinda stuck ...i ve got 3 UN72 of diff lenghts and the 26tpi phil wood rings and finally the phil wood tool
i tried using the phil rings but its not going smooth....too tight for some reason and i did not want to force it and im sure its riding the threads as it does almost half way but gets too tight...the original 26tpi CUPS goes in no problem the phil rings now has some very minor damage to the threads and i did not want to go further...i wanted to have someone re-thread the BB but no LBS has a 26tpi Tapping/rethreading tool.
I dread retapping it to 24tpi but let me know if your successful with LBS rethreading it i might just go that way and use the UN72 24tpi aluminum rings