Thanks for the info guys. I've matched the 22" Westinghouse to a picture of the chassis on the Early Television Foundation site:
Which does indeed look rectangularish in shape but with rounded edges. Speaking of convergence problems on rectangular tubes, no much wonder colour tellies were round right up to the early/mid 60s.
Hope there's still some of those 22" Wesinghouse colour tellies in existence as I would love to see a photo of it.