Gough Thomas must have been a fool as well as 20 years before Sherman Bells' article, he intimated in "Shotguns and Cartridges for Game and Clays" that proper pressure 2 3/4" shells were ok in 2 1/2" chambered guns.
I have never had any problem using plastic 2 3/4" low pressure reloads in such guns.
That being said, RST makes 2 1/2" 12 gauge shells that are milder and burn cleaner than I can duplicate and they deserve your business.