I agree with iiipopes. When, around the age of 16 I passed from " Genis" to the "Bombardino" I remember having had a Bach 7C then, with the passing of the years I progressively moved to larger sizes: Bach 6 1/2 AL, Shilke 51 D, 52 E2, DW 4AL, SM3, SM3U, SM3X and now K&G 3D ( also, sometimes for special sound requirements, the K&G 2,5E)
2007 Besson Prestige 2052, 3D+ K&G mouthpiece; JP373 baritone, 4B modified K&G mouthpiece; Bach 42GO trombone, T4C K&G mouthpiece; 1973 Besson New Standard 3 compensated valves, 3D+ K&G modified mouthpiece; Wessex French C tuba, 3D+ K&G modified mouthpiece.