Big. Those eyelash yarns are tough to work with, and even after years of knitting, I started out using them along with another strand of regular yarn. Mainly because it is difficult to see what you are doing and where to poke the needle. Try a few samples casting on 10 stitches with different size needles to see what you are doing. Are there needle size recommendations on any of the labels?

-Babka

I usually use size 9 with that eyelash stuff...Both when I use 2 strands together and when I use it alone.
Any yarn will be fine with any size needle.....the thing to remember is gauge. ALWAYS knit up a sample swatch to see how many stitches and rows to the inch with the needles you intend to use.

I have made a shawl from baby fine yarn with size 11 needles....lacey and lovely. And I have made a sweater of extra bulky yarn with size 5 needles....very heavy and warm.

It's all about the gauge.
Linda C

oh, I'm excited for you : )! Jealous - but excited !

I love using them as an embellishment strand along with just about anything - currently, I'm working 2 strands of eyelash, and a worsted weight wool on 25's, and felting the results for wrist warmers :)

alone, I would treat them as a #3 weight yarn - the main strand is fingerling weight, but if you knit with a 7 or smaller, you start catching the 'lashes' and turn out looking like thread goobers : )