Thanks to those who answered my request for experience/advice on 205/75/14 not fitting in the spare storage tray. All things considered it seemed easiest to buy a used 185 sized tire. So that's what I did - only going to run it for v. short distance anyway and size difference won't damage anything in 20-30km even on the rear axle. But learned a lot about many details in the process.

One thing this  little episode did - it enhanced my view that these vehicles are often over-engineered in an obsessive way. Surely really superior engineering would have allowed for customers to use reasonable variations in tire size. Hard to understand why VW production cost people would allow design/production/inventory costs that must be higher to have two almost the same sized tire trays. Different trays depending on the trim level of van you bought? Why?  There are many things that make me question the myth of "German Engineering" - this is a small an inconsequential example. More important case is how the Waterboxer continues to be built with a maximum life before coolant leaks of 100,000 km when Subaru has a conceptually similar design putting out more power with no leakage problems and very long engine life. Sounds like stubborn refusal by VW to admit well known problems. Good thing there are so many smart well engineered aspects to the Vanagon package as a whole, to allow us to tolerate the glaring shortcomings.

Alan Pickersgill
85 Transporter converted to Westfalia