The Thomas Cook B757-200 for Canadian Affair which is configured at 35" seat pitch throughout has 187 seats.
FCA B757-200 have 233 seats.
Monarch 235
MyTravel 233
Thomas Cook 235
Britannia 235 (and 1, G-BYAR, with 219 but I don't know the seat pitch for that one or why it has fewer seats)
So I don't know how many seats there would be at 33" seat pitch but you can guess somewhere inbetween 187 and 233.
flyingbee