I'm no expert on Steve Lacy - mainly like Jan Garbarek on soprano. I would not, per se, get into recommending more than what I have usually said about Soprano Planet and Joe Giardullo, who would probably adapt one of his "Open Sky" mouthpieces to your requirements. The Otto Link #12 with 1.5 Marca Superiere reeds is spot on, as you will be aware from your SOTW enquiries. I agree about developing your own sound but do think that it is possible to resemble other players styles, in which I am sure that there is a subconscious leaning in that direction. I am certain that we are attracted to sounds which resonate deep within and which mirrors our own "tuning" as it were. Hence it is likely that Steve Lacy's sound is somewhere within you, as well as within Steve Lacy.
I am North European by birth and musical inclination. When I first heard Jan Garbarek I was deeply moved. When I first heard Sidney Bechet I was completely unmoved, as I am by Steve Lacy. Before getting Joe to make me a soprano mouthpiece I played a Berg Larsen ebonite 70/1 SMS. If you must get a brand name mouthpiece then probably a decent faced Link Tone Edge type piece - larger with soft reeds would be as far as I would go in terms of any recommendation. Reality is I have stopped buying soprano sax mouthpieces.
Kind regards
Tom
I have just received an email from Joe about this question. He would recommend either buying an early Babbitt Link (rare & expensive) or one of his "Missing Links" which is based on one of Steve Lacy's last original mouthpieces (which he sold in 2010 along with Steve's Selmer sax). He could do a 0.070" piece which would work with 2/2.5 reeds - so Marca Superiere 2 strength. Sounds tempting!