question about the 2nd E on the card (your multiple copy gets +x damage, x is equal to the powerful rating of the copys original attack.) is x the amount of damage added from the powerful rating or the printed powerful rating.

Powerful rating, as in the number next to the word Powerful: and amount of damage boost per momentum discarded.

since that attack has resolved, the only powerfull rating that will be there is the printed, unless there is an effect like kanzukiryu kakutojustu's in effect

being that after an attack resolves it returns to printed