Knitting size 38”.
I use a 3.25mm needle for the RS rows (which are purl sts) and a 3.5mm needle for the WS rows (k sts). This way I balance my looser purl sts.

Sleeve decreases as follows:
Decreased the picked up underarm sleeve stitches in every row by 2 sts. Then the decreases went as follows:
1 st in the 10th row
1 st in the 3rd row after that
1 st in the 8th row after that
1 st in the 11th row after that
1 st in the 8th row after that
1 st in the 15th row after that
Then again 2 sts 5cm and 2cm before starting the cuff ribbing.

I started with the sleeve transition chart right below the elbow. In row 3 of repeat #8 I went down to needle size 2.75mm and started with the cuff ribbing. After 3 more repeats I bound off in ribbing after row 6.