It is you, but for some reason I thought you also had one modified by Bill Wrathall, my late friend, that did the job on Ronnie Ross'sHey, I wonder if that is me.
I saw that Derek Nash plays his Conn 12M with a Berg Larsen "modelled on Ronnie Ross's mouthpiece size 130+". He very kindly loaned that to me and I had Dr Ed Pillinger copy it twice - once for me and once to produce a backup for Derek.
My Pillinger copy is a lovely bit of work but while it helps the 12M tuning a bit, it is by no means as "locked in" as my modern Selmer bari.
Or maybe @aldevis means another member.