No one can tell me otherwise, I Love This Yarn is the best yarn ever. Its cheap (because its acrylic), and way softer than any other acrylic yarn ive used. Plus its almost never been split by the hook! I love I Love This Yarn😅
What I would do is when you do your row of fishnet stitch and slip stitch to work in the round, you need to count how many stitches you made and do the same number when working on your next row. Then when you're done with that round, sl st, chain and turn your work and continue working like this. This should make it so its the same size throughout the whole sleeve. If you want it bigger you can reach the point where you want your flare to be (elbow probably) and add more stitches starting there and for the next rounds. I hope this makes sense!!
