Thanks! I think you’re right, after watching through it a couple times I think that Vader’s Castle would need to be almost like a flash, and maybe the Wayfinder or the box should be shown right after. Then progress to showing the Luke and Han visions.
Yesterday I watched Rogue One and realized that at the scene in Vader’s castle, just after it cuts from Vader’s bacta tank, it shows the ceiling of the room and there’s a triangular shape very similar to the Sith Wayfinder.
https://youtu.be/yHeNsynAMgE (at 1:10)
Likely just a coincidence (Sith are frequently associated with triangular/pyramidal shapes, such as their holocrons or temples), but maybe a version of that shot (reframed or edited, since Krennic’s shadow shows in the lower right corner) could be repurposed for Kylo’s vision along with the backview of the castle (at 0:24), while leaving the panning exterior shot of the fortress for the actual Mustafar sequence.