I’ve tried more tubes in this variant than I would care to mention. Oddly, favorites were the Amperex 6DJ8 with a white globe. I’ve never seen these anywhere else, and they sounded better than other Amperex 7308 (military spec) with white lettering that are $$$, despite the 6DJ8 spec supposedly being the lowest of 6DJ8/6922/7308. If you can find any Amperex 6DJ8 with a white globe on em, try it out.
The Amperex JAN 7308 is white good as well, as is the Reflektor 6N23-P. The latter are still available on Viva Tubes, where I’ve purchased some in the past: