Okay, so I am still working on some scarves to learn some advanced stitches - I just learned to cable two days ago and although the stitches seem pretty tight...they look GOOD

- but I am ready to move to other things. Especially since here in VA, we've had mostly non-scarf weather so far!
I want to start a hat and the question I have is pretty basic - most of the patterns I look at have COs of 80-100 and yet the pattern calls for needles between 7-10 - it doesn't seem to me that all those stitches will fit unless you get a longer set of needles (I am talking about straight needles - haven't gotten into dpn's yet and although I've bought round needles, haven't tried those yet either). It seems that the longer needles are kind of bulky to work with.
Thoughts or do I just go for it and try it?
