I have been told by someone who should know that a 2a3 is, essentially, two 45s in one enclosure. When I used to own a 300B amp I was always a bit puzzled about the reverence shown to the 2a3. I wondered why praise of the 300B was not universal? Why was it often considered as "behind" the 2a3 and the 45?
Then I got to hear the 45. The midrange emphasis of the 300B was clear, as was the more extended frequency response of the 45. The tone and inner detail of the 45 was breathtaking (my room, my speakers, my listening preferences, YMMV).
So, not exactly a response to the OPs original question, but I wanted to add my .02...