Timing of Astrologic Sense (Balanced Arrangement 15th level ability)

[Hiruma Kai]

Astrologic Sense:

You briefly meditate on your connection to the cosmos and how the interplay between stellar forces can affect your foes. For the remainder of your turn, if an action you take would result in a variable effect based on your attunement, determine the result of both effects. If this determination requires you to roll damage, then roll the damage. If it requires the target to make a save, then have the target roll the save. This only applies to damage or effects that are specified in the attunement options of abilities, so things like the damage roll for your solar weapon are not determined in advance.
Once you’ve determined the possible effects for both attunement states, you can select which of the two you would like to have occur, regardless of your current attunement. If the ability would change your state, you count as being attuned to whatever attunement state you selected to take effect.

Stellar Rush:

You rush forward, empowered by your stellar energies, getting into the thick of combat with ease. Stride twice. You gain a +10-foot circumstance bonus to your Speed during these moves.Graviton-Attuned When you finish your Strides, enemies within 15 feet of you must attempt a Fortitude save against your class DC. On a failure, the foes are pulled directly towards you, ending in an adjacent square if possible. You select the order which foes are moved.Photon-Attuned The squares you moved through during your stride are suffused with solar energy until the start of your next turn. Creatures on each side of the squares are concealed from creatures on the opposite side. Creatures in these spaces are unaffected.

Stellar Rush has two different timings when the attunement benefits apply.  Photon attunnement applies as soon as you move a square, while Graviton applies after you finish both Strides.  When do you make the saving throws for the that Astrologic Sense calls for before picking which attunement to apply? Before you take the two Strides?  Do you get to pick a point on the map and ask who would fail saves if I moved to spot X?  Can you choose not to move to spot X if you don't like the results? Do you pick multiple spots to test saves on and then move to one of them?

In general, would you roll all potential saves/damages before you actually take the action, which might have a variety of end points? An example use case with Stellar Rush would be great for its intended usage.

[Torradin341]

As I read it, the only thing it's letting you play out are the effects of the attunement state, nothing else. For Stellar Rush, you are taking two strides and then, after you finish, your attunement does something. Photon lights up the squares you moved through and you cannot determine those squares until after your movement ("The squares you moved through during your stride are suffused with solar energy" - past tense). Graviton forces a fort save and effect on enemies based on your end position, which you cannot determine before you end your move. Both determinations happen at the end of the move.

My best reading is that you commit to your strides, then determine the outcome of Photon-attunement (easily calculated - what squares did you move through?), and Graviton-attunement (what enemies are within 15 feet, what are their fortitude saves vs class DC, which ones failed, what order will the enemies be pulled in, where do they end up), then you decide which attunement results you want to have happen.

[Hiruma Kai]

Oh interesting. I originally read Stellar Rush's photon attunement as creating the concealment squares during the stride, and thus might in theory have some effect during the movement due to reactions.

So with your help, I now realize that the wording implies the concealment squares pop up at the very end. Which is a very different cinematic feel. More like casting a spell by tracing a path rather than leaving a trail.

Thanks for the clarification.