If I want to make a shrug in worsted instead of bulky weight yarn, first of all can I do that, and do I buy more of the worsted than what is called for in bulky weight? Also, what size needles should I use if making size small?
what pattern are you using? a lot of it depends on gauge (st and rows per inch).
If you cant find a bulky yarn you like so are going to use worsted, you will probably have to adjust the guage somewhat, which would meen altering the number of stitches you cast on and so on to accomodate.
The size of needles is again a question of gauge than the size of the item. It is best to use the size needles the yarn you choose calls for, in order to get a nice fabric.
You can substitute yarns, but using thinner yarn and smaller needles will give you a smaller size. Do you'd need to follow the pattern for a medium or large, depending on your stitch gauge, though you'd make the length you need for the small. You can use size 8-10 needles for worsted, decide which knits up how you'd like.
The one project I did, that called for Chunky and I used Worsted was a cardigan sweater. I can't remember exactly what I did...but I think I used the pattern needle sizes, and made a larger size. It was very....um...loose. The stitches were very large, and the project hung very..well...limp....
But then it was a large project.
If I were to do it all again, with the same specs...I would likely use a smaller needle and up the pattern size to jumbo to get the results I wanted.
I didn't much care for the loosey gooseyness of it it all....