Nice, so that also suggests a production to sale time frame of around 8 weeks. Neat as a pin!
Back to the plastic wheel topic, from what I gather, you are suggesting we ignore the ads of 28 November 56 (tin wheels) and 6 of Feb 57 (black plastic) as demonstrative of a transition and rely on solely on the ad of 30 October 56 to establish the introduction of plastic wheels, which to my eye could swing either way? I'm probably relying to much on tangible evidence, but that's the academic in me
Given that you think the production figure of 143,000 p/a by 1958 be ignored, and would be allot lower (ie 60,000 for 1956, as you said) that would average out at 5,000 per month. From June - January would see them at #35,000. This would suggest that mower number 38952 would have been manufactured around the end of January, and then left on the shelf for 7 months - sounds like a stretch
As you said, I think we need to find that illusive Model 2 ad for a little more clarity
