Signature spells

When I read in the spell generation section I noticed that signature spells can be carried by different wizards in the same army.

So to my questions:
1. Can you cast the same signature spell twice in the same magic phase with two different wizards then of course?
2. If yes to above. Can I for instance cast Wyssan’s Wildform on the same unit twice in the same magic phase thus giving it +2 in strength and toughness?

Thanks in advance.