Wine cozy

this pattern calls for #4 needles and WW yarn; I dont have #4, can I use my #8 and sport weight yarn? would it be about the same size?

It probably calls for 4’s and worsted weight so you get a nice dense fabric. 8’s and sport weight will give you a light, airy fabric. You can try it and see what it looks like, but it won’t have the bulk of the original.