The sweater that i'm working on calls for a three needle bind off. The work was done on size 7s... but i only have two of them. Is it 100% imperative that the 3rd needle be a 7 as well? or can i use an 8 or a 6 ?
It's not imperative. Actually, I think your best bet would be to put one of the shoulders on the 6's and use the 7 to knit--the needle you knit with determines the size of the stitches.
Thanks! that is very helpful. i would have done it the other way.