This is a very interesting thread.
When Spey casters are separated by an ocean strange things can happen. Cast evolve like the lemurs in Madagascar.
I've watched the video and the way Dana is making the spiral spey is different to the way I have seen it done in the UK.
In Dana's Spiral spey there is a Long initial straight lift followed by what looks like to me, a straighforward snake roll.
I would say (from a UK perspective) that both of these casts are snake rolls that start with the rod in a different position in regards to the dangle and one has a straight lift.
A Spiral spey, as I have seen it done over here is a Quick, small spiral used to lift the line (snake lift, spiral lift) into a fairly standard Spey back sweep.
In fact, the opposite to that Dana shows. He makes the Spiral late, we make the spiral early.
Two countries separated by a common cast?
If we look at what defines the snake roll in that the line is taken over the top to form the D anchor both of the cast Dana shows are a snake roll. One has an immediate curved lift and the other a straight lift followed by the same movement. I'd personally say they are both the same cast, one having an extended lift.
The Spiral we use is the same start as Dana's Snake roll but smaller and pulled tight to make the C shape travel faster down the line, followed by a standard Spey sweep. The line does not travel above the rod. This makes them two different casts.
Saying all of that, I've not seen every caster in the UK perform this cast and there could be many that do it either way.
How would those on the other side of the pond differentiate the Spiral Spey seen from Dana and the Spiral (or snake) lift?