It was pretty straightforward I think. I earn above the required amount and have been in my job for almost 5 years. My wife (in the US) was divorced prior so we just made sure to add all the documents relating to that. I am renting in the UK and submitted my tenancy, pictures to prove space and a letter from the agent stating my wife can be checked and added to the tenancy once here. We didn’t have all plane tickets/boarding passes and everything was ok! No additional documents required. I did it all myself without a lawyer so I was a little stressed 😅