Shadowcraft Mage vs. Metamagic

[Pippin]

1. Let's say my Shadowcraft Mage is about to cast a twinned Silent Image. When exactly does her Shadow Illusion class feature apply? Is the spell twinned before the spell is altered? If so, can I choose to mimic two different spells?

2. Let's say my Shadowcraft Mage is about to cast a repeated Silent Image. When exactly does her Shadow Illusion class feature apply? Is the spell repeated before the spell is altered? If so, can I choose to mimic a different spell during my next turn?

[noob]

The altered spell functions identically to the shadow conjuration or shadow evocation spell
Does means that it works like that spell but it never says it does keeps the meta-magics.
so I think that you cast the spell like if it was a shadow conjuration or shadow evocation spell and that if it keeps any meta-magics is up to the GM.

[Pippin]

Does means that it works like that spell but it never says it does keeps the meta-magics.
so I think that you cast the spell like if it was a shadow conjuration or shadow evocation spell and that if it keeps any meta-magics is up to the GM.
Well anything is always up to the DM. I was just hoping that there was a general consensus as to how it works.