Im running #1 gami octo hooks on the bigger fly's/winter patterns. I'm working on a batch for a buddy that will be quite a bit smaller than my normals. Which overall means shorter shank, lighter stinger wire and yes a smaller hook, most likey a #2 owner. Theres nothing worse than straightening a hook out on any fish.

Most of my personal ties for winter are roughly 2.5"-5". Anything above 3" ill run a #1, tho it really depends on the tie. If its a light and sparse 3." ill drop down to a #2.