OK I get the N American/British differences (worsted/aran etc)...but how do you know what weight a yarn is if it doesn't tell you on the label? I know you can sort of work it out by the tension guidelines, but that's quite hard for a near beginner like me. Is there an idiots' guide to this? Or is it something you just get a feel for?
I really want to knit a gorgeous top from ALterknits, and it specifies Jaeger Trinity. I've had a look at some and don't really like it, plus the colours are not very me, and quite limited. How can I find a yarn that is exactly equivalent in terms of knitting up?