Steve, on the NIFHS website under resources, use the NIFHS Genealogy Search Engine and enter ‘tailor’. I think you will be busy for weeks
I also suddenly remembered occupations being listed on gravestones in Clifton Street Cemetery ie home.glenravel.com here are just two examples of no doubt many.
The registry 1832 [page6]
July 5
Hugh Marshall
Aged 60
Tailor Master
Pottinger’s Entry.
1833
May 10
Robert Allen
(Consumption)
Tailor
Ann Street
From and born near Randalstown
His brother resides in Orr’s Entry
I stopped there, I didnt look up Stevenson or Twig, I was searching by occupation. its a great website. hoping its sets the scene at least in Belfast. Tailors kept records, perhaps PRONI or the Ulster Folk Museum will have some records. Perhaps the cloth manufacturers sellers eg Donegal Tweed may have kept records, incidentally while working in Belfast, in the late 1960s/70, I acquired via a friend Andrew Boyd, a roll of light grey Donegal Tweed straight from a mill, and couldnt find a cheap tailor to make me a suit. I still have the roll wrapped up somewhere. Must get it out.
Good luck, Jim