Did NOT do a fabric swatch and so by the time I had 4” to test guage in the garment, I found I had 18, not 16 sts per 10 cm. So I simply kept doing the sleeve and front increases until I got to the size 4. An easy modification for beginners.

I did a half twisted rib on the bottom hem for 3 rows and then changed to full twisted rib for the remaining hem so there could be a slight reduction in size using the same size needles as the body. ( I wasn’t seeing a reduction with half twisted rib alone)

Did no sleeve decreases. 65 sts
Kept the needle size US8 for sleeves.

Reduced sleeve to 50 sts on first round of 1 x 1 full twisted ribbing and US 6 needle

15 rounds then italian bind off