English wool used a 560 yard skein - if 4 skeins of the finished yarn weighed 16 oz that would be 4ply yarn. It would be - probably - 2/8 worsted count as it would be 2 ends twisted together of wool spun to 8 skeins to the pound.

Worsted count, Cotton count and High Bulk Acrylic count are all being phased out in favour of the metric count - though it is less useful to hand knitters as the density of the yarn is not taken into account - but industry seems to be coping just fine.

Wraps per inch is something I only came across when I started dealing with hand spinners.

I have a fishing line measurer and accurate scales from the time I used to make yarn to sell and needed to ensure that I was getting the correct length per weight.

Anne the Pleater