1st ?: You can either estimate about 1" per stitch in a worsted weight yarn.
OR cast on ten stitches, take them off the needles to see how much yarn you've used, then figure how much you need for the number you have to cast on. I prefer the second option if I'm casting on anything over thirty stitches.
2nd ?: When you're typing get to the place you want the emoticon like here maybe
then click on the icon you want (knitting away) :XX: and it will end up in your message, but it won't look the way you think it should :rollseyes: until you preview your message.
Welcome to the KH funhouse :D and
Happy Knitting (and emoting) :XX: :XX: