Speedmaster model range

[NDA]

Any Speedmaster experts on here?

I've long been tempted by a Speedmaster, either new or nearly new. But am a little put off by not knowing quite which one to go for as there's quite a range - there seem to be a number of different models, all very similar looking. I'm told a manual wind is better than an automatic. Are they all the same size - for example?

An idiots guide from someone who knows would be very welcome.

Thanks

[NDA]

That's really great information - many thanks... Particularly Unclepat, I learned a lot from that post.

[NDA]

All very interesting replies.... I think I'm now zeroed in the model that I want - how many size variants are there?