1.Do one less round for your granny squares e.g. 4 rounds instead of the 5 for the dk version, use a 4.5mm hook for Aran weight yarn.
2. You should have 26 stitches for your rib top and bottom of your wrist warmers, use a 4mm hook for your ribs to keep them tight.
3. So you should have one stitch above both of your seams and one stitch of either htr or tr in each and every treble of your 3 treble groups from your granny squares (total 26stitches )
4. Then 14 htr evenly around your thumb, ready to work your ribs.
We used Debbie Bliss Cashmerino a blend of cashmere and merino super squishy ! Enjoy and happy crocheting Xx