The Right Yarn for Curtains?

Hi everyone :)

I haven’t really been interested in curtains and such until now, but I’ve just been asked to crochet some. Of course, I’d love to do it :)
Now I’m wondering: What kind of yarn should I use? I have absolutely no idea what’s best or what I should look for.

What do you guys usually use? Material, thickness, hook size,... :)

(Please don’t post any links—they’ll just get deleted anyway :))

Best regards
Tina 

Hi Tina!
My aunt used to crochet fine curtains.
She gave me the following details:
dimensionally stable cotton crochet yarn
size 5:
hook size 1 3/4–2
yardage 100 g = approx. 400 m

For thicker curtains
size 10

Thank you so much—that gives me a good starting point :) 

Hi Tina,
I always use Uschi Filigran Cotton 529m/100 gr

Best regards, Tanja