I used the same Corriedale from my fibre stash for the thrums and pom-poms (as with the Cadeautje slippers). The tea cosy, like the slippers, used almost equal amounts of yarn and fibre by weight. The cosy used 51.9 grams of yarn and 53.8 grams of fibre (including the pompom).

The cosy is made with about 4” of positive ease in the circumference, and about 2.5” over the top of the pot -- I could even have added more, but the thrums will flatten over time and I think this will continue to fit well instead of getting overly loose.