There’s tons of weird discussions around this on the interweb
- Paul McCartney is quoted as stating that Lady Madonna was recorded with the Mrs Mills piano
- Ken Scott, who is said to have been involved in engineering Lady Madonna, is reported to have stated that it was the Abbey Road Studio 3 Steinway Grand
- According to the “Beatles Bible”, the video footage for Lady Madonna was shot with the Beatles recording Hey Bulldog at Abbey Road Studio 3
- Mark Lewinsohn (Beatles biographer) seems to have confirmed that Hey Bulldog was recorded at Studio 3
- according to people who have actually been to Abbey Road (I haven’t), Studio 3 is upstairs, while Studio 2, where the Mrs Mills piano sat, is downstairs. There being no lift at the time, it’s rather improbable that the Mrs Mills piano was used in the Bulldog recording
Overall, @Corky’s hypothesis that a Steinway Grand was used for Lady Madonna, seems to be the most probable one . And based on the information available, it also looks plausible that the same Steinway Grand was used for Hey Bulldog
Still, getting the Mrs Mills VST is definitely a no-regret-move at the price - and if it sounds and feels good for playing Hey Bulldog, then I’d say by all means go with it!
With live piano, it’s more about whether I feel good playing it in a band context rather than the last 10% of authenticity. As long as I’m in the ballpark sound-wise, it’s good. I’ve often found that the “best” and most authentic sample sets don’t really cut it in the heat of the battle - I’ve yet to find a more “honkytonk-ish” piano sound that I really feel comfortable with on stage. Currently, I fiddle with Pianoteq 7 and modifying some of their models, but I keep missing that last bit of “punch” that allows me to kick through the mix when I need to, while still giving me a comfortable mid-velocity base tone and a smooth transition between the two…
For clean, straightforward piano, my Addictive has remained at the center of my setup, but for some softer songs or balladesque intros, it just hits too hard (too much hammer noise) for my taste, so I’ve jumped back and forth between other options, but never really found something that makes me feel as “at-home” as the Addictive.
But that’s just me…