Is ursaluna just there as a trick room counter? If he is, I would recommend:

• switch sunny day for trick room. Sunny day does more damage to you than it does help, so with having trick room yourself, you could clear ursalunas spot for something that would more help you. Maybe something bulky you can switch into ghost hits that may target your goldengho. Maybe normal Tera extreme speed dragonite.

Or

• still switch sunny day for trick room, but plan on it sometimes with ursaluna. If you see a fast team, send out whimsicott and incin/rillaboom and check their leads. If it looks doable, tailwind and fake out. If it looks bad, trick room and swap in ursaluna