Can a sorcerer make independent spell-effect choices for a Twinned spell?

Can a sorcerer make independent spell-effect choices for a Twinned spell?

For instance, the Polymorph spell can be used on willing and unwilling targets; the unwilling can make a Wisdom save to avoid the effects.

The sorcerer’s Twinned Spell metamagic option creates a second instance of the same spell on 2 viable targets within range.

Does Twinned Spell force me to polymorph both targets into the same thing, or do I get to choose what each instance of polymorph does independently?

In this case I am trying to turn my friend into a T-rex, and an enemy into a goldfish.