You have already been provided with a response on another site. Accordingly, the Hua Hin Immigration Office accepts applications up to 45 days prior to the expiry of your current permission to stay.
Should the application be submitted with 30 days or less remaining on the current permission, you may be assured that both the income certification issued by the embassy and the extract from the Amphur confirming the marriage will be deemed valid and accepted by the immigration.
To fulfill the financial requirements, you will need to provide evidence of funds amounting to 500,000 THB in a bank account. Regarding the visa validity, it is issued for a period of five years with a permitted stay of 180 days per entry within this timeframe.
If the immigration office in question accepts monthly transfers of income or pension from abroad as grounds for an extension of stay based on marriage, it will most likely also require that the transfer be recorded as an international transaction. While some applicants have managed to achieve this when using Wise, it is something you will need to verify independently.
To clarify, you're seeking a temporary residence permit for one year based on marriage, which requires a Non-Immigrant visa. You can apply for a 90-day Non O visa outside Thailand or switch from a tourist visa in-country if you have a bank account.
Over time, an increasing number of immigration offices have discontinued the practice of accepting monthly income or pension transfers from abroad as grounds for extensions based on marriage. While some offices may still accept this in practice, as evidenced by feedbacks, the prevailing rule is now otherwise, and the alternative has been formally removed from the regulations.
You’ll need to ensure that funds are seasoned for two months in a bank account prior to applying for the one-year extension of stay, which should be factored into planning.
Then you are not on a legitimate stay if you have used an agent to circumvent the formal requirements for an extension of stay. At some point, you may face consequences due to the current crackdown on banking services.