If the spell that's copied has an X whose value was determined as it was cast, the copy will have the same value of X.

If, while you control Spider-Verse, you also control a legendary Spider permanent and a single legendary non-Spider permanent with the same name, the legend rule will not cause you to put either one into your graveyard.

If, while you control Spider-Verse, you also control more than one legendary non-Spider permanent and at least one legendary Spider permanent all with the same name, the legend rule applies to only the non-Spider permanents. You must choose one of the non-Spider permanents to keep and put the rest of the non-Spider permanents with that name into your graveyard. You may not choose one of the Spider permanents to keep and you may not put any of the Spiders into your graveyard this way.

Once you choose to copy a spell with Spider-Verse's last ability, that ability won't trigger again for the duration of the turn. Any instances of the ability already on the stack when you choose to copy a spell will have no effect.