Agreed, maybe Innocent will show how she does magic.
Dual symbols turning in different directions I take it as since one is already rotating that way, the other will be the opposite; speed of turning does not bother me either but changing direction during casting?
Then I'll take my last option, it is completely random
Yeah, but still, IIRC Alicia was said to have some magical talent, if nowhere near Precia or Fate's...
As to your question, I don't think there is a definitive answer to it. I vaguely recall that some spells summon two circles, which rotate in different direction, while others' circles rotate faster or slower and even change direction...
I can say that two characters are canonically left-handed, Nanoha and Alicia, and only one, Teana, is specifically stated to be ambidextrous. However, there may be other candidates for ambidexterity (Tre, Sette, Deed).
The mighty wiki editor has spoken! Thank you for this information.
However, I would like to point out that Alicia did not cast any spells canonically so she cannot be used in my question.
Maybe in the movie 1st (waiting for 2nd to be subbed) she did as Precia was losing it about Fate's magic being different but I don't recall an actual scene with the magic circle beneath her.