mr1212,
Same as you, I also bought size 80. The saleslady said size 70 is OK but my sister said 80 is better. I also bought it at Jusco. Which one you bought? I have bought 8 pcs with 4 are 夾綿 and I think it is too much. 2 with priced at HK$39 each and the other at HK$49. I have washed those with 夾綿 but they did not 縮水.
Will you buy 羊毛內衣?
It may a bit bigger but I have no idea whether the baby will grow bigger for the next few months as the 底衫 may wear till Feb. I may put a thin 底衫 under the '甲'綿. If you plan to buy few more, you can buy 1-2 pcs at 70 size...
By the way, the HK$49 style is thicker and warmer than HK$39.