The mix of winter baits I would throw gets pretty small. Float and Fly, Small skirted jig with trailer, Jerk baits. (100 size max), hair jig or in my case a Zig Jig, Ned Rig, tuibe or Ika, and a Hula Grub on a jig head. That's about it Most of those things are smallish, but more a reduced speed/activity level from warmer water periods than reduced size. I don't throw a lot of stuff larger than that when the water is warmer.
If I had to do so, I could be pretty happy heading to the river when the water is cool/cold with one rod and a dozen 1/8 oz Zig Jigs.