I'm knitting blocks and strips for an afghan and have been using a size six circular needle. Most of the block designs had me casting on 44 to 46 stitches. There are two blocks I would like to knit. For one I would have to cast on 54 and another 58. I may be able to fudge a little and cast on 2 to 4 less stitches for each block. But I was wondering if I could go down a needle size or two to insure that it would be close to the size of the other blocks. Because this is just an afghan I don't think it would be a big deal. Yes I'm being lazy I don't want to do a test swatch.
And just wanted to know if there was a average difference per needle size. Thanks in advance