A recent discussion on a respected fly dressing forum made me think hard about the unconscious choices I make when selecting hooks for my imitations.
I like my flies to be roughly equal to the size of the insect being imitated, or slightly above (I subscribe to the supernormal stimuli school of imitation). In river fishing it usually means tying mayfly imitations on sizes # 14 - #18, and caddisfly ones somewhat larger.
On the other hand I am really fond of Kamasan B160 hooks in size #10. They are sharp, reliable and can be had in a handy & economical package of 100 hooks. Size #10 should be a tad big for regular river fishing though.
The trick is that the B160's are 3x short hooks, which means that they are about the size of regular #14 hooks. About right for most river fishing.
The picture shows a #14 Hanák H130 BL hook (my favorite dry fly hook), a fly tied on a Kamasan B160 in size #10 and a regular size #10 dry fly hook - a Hanák H100 BL, as I could not find a properly sized H130 BL fast enough.
The moral of the story is that while manufacturer labels of hook sizes and shapes and whatever are important you should not trust them too much - your own judgement matters much more!