: I have never met one person who can demonstrate a feather of 60 degrees or
: more
: and not have the control hand wrist bend somewhat when the opposite blade is
: in the water

By "straight wrist" I mean the center of the paddle shaft is aligned with your forearm. If you go with the back of your hand describing a straight line with your forearm, the paddle is below the center of force created by your arms and your wrist muscles would have to work at lifting your wrist to maintain the pushing force. Your wrist should be slightly bent upwards so the muscles controlling your wrist are not required to sustain the force of your paddle beyond maintaining balance with the load centered in your grip. Maybe a better word would be "neutral wrist".

The neutral wrist position on the lower hand will be more straight because your wrist is in tension and all the force of the paddle is held by the hook of your fingers. The degree to which you curl your fingers will effect the angle of the paddle blade and how much your wrist straightens.

This slight motion from straight on the pull to slightly bent on the push is about all that is needed to adjust a feathered paddle. Even with a high feather angle you don't need to move your wrist significantly beyond what is natural between pushing and pulling.

: In Alaskan/very cold waters we prefer solid foam floats which do work better
: flat which puts the other blade perpendicular to the deck.

In 30+ years of paddling I have never used a paddle float for anything other than a pillow, but have often had to fight a serious headwind. I will sacrifice some utility in a rare paddle float situation for many easier days in head winds. Just being less tired by the slog will mean I'm less likely to need the float. Its true that solid float is better, but even they float on their side, I would just deal with it on the rare occasions.

FWIW when I do practice with a paddle float, I do not strap the blade to the back deck, but instead grasp the paddle against the back of the coaming. This has its own set of advantages and disadvantages, but that is a different discussion.

: If it is still "a little" why do it if you are not in headwinds.

Because if you are switching the paddle orientation at every change in wind direction you will not have the instinctive ability to put the blade where it needs to be in a sudden brace.

: We pay attention to a lot of "little" things to make our kayaks
: perform better, reduce drag, make our strokes more efficient, save energy,
: prevent hypothermia, etc. This is just another little thing that has
: better ways or advantages to use when it makes sense.

The difference in a headwind is significant, everywhere else it is minor. When you are slogging for hours against a headwind, every little bit you can make it easier is welcome. When you are scooting down wind, you just don't see the need for it to be a little easier yet.

: Learn both, practice both, use what works best and is most advantageous for
: the conditions and your physiology.

I don't agree with the "use both" philosophy. I think people are better off learning and getting comfortable with one or the other. Maybe try both for a while but as you get more experienced choose what you like better so you can concentrate on getting your other skills as quick and instinctive as possible.