I heard both 2a3 and a 45 on my Edgarhorn speakers and of the two preferred the 45. The caveat to all of this is the design quality of the amp....power transformers/coupling caps/power supplies etc. I also owned a top quality 300B but the 45 was at least an equal match in musicality with the 16 OHM/107 DB load.
You will notice little difference in power between 2a3/45 but I predict their are more 45 tubes out there to choose from the NOS tube days as they were used in tube radios of yesteryear. I owned the Yamamoto 45 and still own the Korneff 45 and prefer the Korneff for the sound you mention.......again same tube different design. Same ole story. My opinion is go with a used 45 if you can find one but quality of design matters a lot with either amp.

