If, as you say, you are married to a Thai, you can get the 60 day "Visit Thai Family Extension" to give you more time (your wife has to accompany you when you make the application).
Agreed, make a careful note of every requirement and ensure that every one is addressed and has relevant documents attached and referenced to support each one no matter how small it may seem to you. You will be her financial sponsor so make this clear with adequate bank statement and include where you stay and where she will be staying.