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Have a question about measurements. I have a 10+ years old black N1 with the much thinner alpaca insulation, size M. Measured several times, very carefully and my old size M has the measurements of todays size S. Does the much thicker insulation of the new N1 justifies the measurement difference? In other words should I stick to size M with the new one because the size difference is caused by the thicker insulation? Thanks.