Air Cell stitch

So, I have started another afghan with the Alpaca yarn. This time, I am trying out the air-cell stitch. It's my version of the stitch. I know this is what was wanted for the blanket. I honestly don't know how this will work in this yarn, as the yarn is thick and thin. But, it's worth giving it a try, right? I will pist progress ad I try this out. I have cast on about 350sts, I think. Or is it 250? I will have to count them later. I do know my circular needle isn't quite long enough, but it will have to do, I don't know if I can get a longer needle.