Winston was never 'the spaz'. He's just an everyman working Joe who needs a job.
"If there's a steady paycheck in it, I'll believe anything you say"
In fact, Winston's race is never a factor in the film. I've only just found out that the "I've seen shit that will turn you white" joke is race based. I saw the film at the pictures in 1984, I'm 38 now and just thought the joke meant "white as a sheet". Race was never an issue with him