What is Starlight Glade?
Starlight Glade is the far end of the route in the official description, the last name in the phrase from the Meadow all the way to Starlight Glade. Reaching it means the seed has passed the zones in between. No distance and no final multiplier were published.
How do you get Starlight Glade?
Throw far enough to reach the end of the published route. Training and timing are the systems the developer ties to distance.
How do you use Starlight Glade?
Use Starlight Glade as the distance goal. Arriving there boosts luck by the zones passed. It does not guarantee a Secret.