Dualcaster Mage
Oracle Text: Flash
When Dualcaster Mage enters the battlefield, copy target instant or sorcery spell. You may choose new targets for the copy.

Twinflame
Oracle Text: Strive — Twinflame costs 2R more to cast for each target beyond the first.
Choose any number of target creatures you control. For each of them, put a token that's a copy of that creature onto the battlefield. Those tokens have haste. Exile them at the beginning of the next end step.


If twinflame is casted without any target, then, in response, the mage is casted and as it citp its trigger effect well trigger ... can we change the number of target as well as the target ?
Number of target being 1 and target being the mage itself

thank you