I made this shirt for my grandson age 1.6 in a size 18- 24 mo, in flannel fabric, for the holidays and it fit well. The cuffs would not button around his wrist. It may be because the flannel fabric is thick? I thought it was the length of the sleeves but the cuffs were at his wrist and would not button. Would I just add onto the width, of the cuff pattern piece, and let that width extend beyond where the the bottom of the sleeve is sewn inside the cuff?