Re: Rod Spine...up or down?
I don't know anything about building rods, but I do know that all of my rods twist on a backcast in a counterclockwise direction looking down from the sky. And they twist in a clockwise direction on the forward cast.
How I know this is because I line the guides up 45 degrees out from my right side instead of in line with the reel like most people. That way I never get "haul jam" or haul "lock up" anymore, always have the same minimal friction on the haul, and get a better and more consistent shoot as a result. A lot of the competitive distance casters I see twist the rod 90 degrees on the forward cast, which amounts to the same thing I do - just an extra 45 degrees.
I can twist the top section alone of any of my rods 180 degrees (including 12 wts) holding the tip top between thumb and pinkie finger only and twisting. So I know that when I am casting, the tip top is twisting toward the direction of the line as the rod loads.
What a lot of rod builders will do down here do now (if the customer wants) is run the guides on big conventional rods in a spiral so the tip top is upside down relative to the reel. This precludes the inclination for the rod to twist while fighting fish - which I recall happening as a kid while fishing solid fiberglass conventional gear.
It really makes it hard cranking while your other hand is battling a lot of torsional strain as well as regular down strain. And every half turn of the crank is adding to the torsional strain on the other hand because you have to crank in the same direction as the torsional strain your rod hand is working against.
I didn't notice any difference in accuracy when I started twisting my rod sections out. And I've not broken any rods catching large tarpon with them twisted either - though I have had them wind up straight again at the end of a fight with one.
So I don't think that rod twisting while casting or fighting fish does any harm at all to a decent fly rod. But that is just the opinion of a fisherman, not a rod builder.