The intended gauge is 18sts and 26 rnds per inch. My yarn is Paton's classic wool worsted in natural mix colorway.
I tried my gauge with two different needles: US 8/5mm and US 7/4.5mm. The following pictures will demonstrate how being off on gauge will produce ill-fitting results. Both gauges are exactly the same number of sts and rows and lightly steam blocked. Do you notice the difference in finished size?