Here are some non-binding suggestions for your fashion choices for both the Thai ceremony in the morning and the Western ceremony in the evening.

Some general remarks:

• No suit policy. Suits, as well as neck or bow ties are not mandatory. You are still welcome to add them to your outfit if you like.
• You don’t need two outfits. It’s totally fine to wear the same outfit for the morning and evening sessions. Keep in mind that it can be quite warm, so it may be more comfortable with a second outfit for the evening.