@Jared ********
Mid-market rate? Or say the Bangkok Bank TT buying rate, which would be the one that applies when you actually transfer money. Alternatively, the one that Wise uses for the amount you're trying to show (keep in mind that for large amounts, Wise won't quote if it's above 50,000 Baht as you can only transfer amounts above this to 3 banks, including Bangkok Bank).
Therefore, as a reliable exchange rate, I'd use the Bangkok Bank TT buying rate.