I splurged and ordered a ten pack of Bates Bamboo handle hooks and a nine pack of Boye ergonomic handle hooks. The mm size of each letter size is not necessarily the same. I had no idea there was a difference between brands. Is that difference enough to make a difference in gauge?
hook letter and number size/mm
Boye: D/3.125 E/3.5 F/3.75 G/4.25 H/5 I/5.25 J/5.75 K/6.5 L/8
Bates: E-4/3.5 G-6/4 US7/4.5 H-8/5 I-9/5.5 J-10/6 K-10.5/6.5 L-11/8 M-13/9 N-15/10