Easily the best tubes I have heard are the 7730’s in various configurations (halo, D, long or short plate)So according to present forum consensus, which are the bestest of best 12AU7 tubes for the LP, modded and/or unmodded. I am only referring to present reigning contenders for the title of "best." I know that such contenders could change at any time with ongoing/future tube research and discoveries.
BTW, in case this matters, I like my sound to be airy, detailed, and well-extended at both ends, without any harshness or fatigue. Thick and creamy mids are also welcome, but their absence is not a deal breaker, as long as those mids are not "thin."
They have a presentation that i think is best described as cinematic. It’s extended and airy as you desire but are not really very thick in the mids. They produce a very wide soundstage that brings the LP to another level. Not the strongest bass, but clear and satisfying.