Collected Conjuring resolution - doublecast and stone rain

Collected Conjuring reveals Doublecast and Stone Rain

Collected Conjuring rulings:

2019-06-14: Each individual spell you cast this way must have converted mana cost 3 or less. Their total converted mana cost could be greater.

2019-06-14: You must cast any of the exiled cards you wish to cast while Collected Conjuring is resolving. You can’t cast them later in the turn.

2019-06-14: You may cast the two sorcery cards in either order. The second is cast before the first resolves.

2019-06-14: If a spell has in its mana cost, you must choose 0 as the value of X when casting it without paying its mana cost.

2019-06-14: If you cast a card “without paying its mana cost,” you can’t choose to cast it for any alternative costs. You can, however, pay additional costs. If the card has any mandatory additional costs (such as that of Tormenting Voice), you must pay those to cast the card.

Based on the bolded oracle, does that mean regardless of how I stack the order of Doublecast and Stone Rain, I can never copy the Stone Rain in this case? Since the Doublecast would not have yet resolved when I put the Stone Rain on stack?

Any light on this matter is much appreciated.