Exiling two copies of the same card with Spellweaver Helix, like Slime Against Humanity, does not produce a copy when you cast the same card as both exiled cards from your hand
Can confirm that in testing Spellweaver Helix does not create a copy of the imprinted cards if they share a name, and this is incorrect behavior since one of the rulings for Spellweaver Helix calls out that you should get a single copy in this scenario.
If the two imprinted sorcery cards have the same name and a card with that name is cast, only one copy is created, not two.(2004-12-01)