@Jamie *******
you need to start out with a single entry Tourist Visa. It will give you 60 days admitted stay plus 30 days extension. You will have to get married within the first 75 days after entry, because in order to apply for the conversion to the in-country 90-days Non-Imm-O visa based on marriage with a Thai, there need to be 15 days left on your original visa. Once issued, you can apply for the 1-year extension of stay based on marriage 30 days before the Non-O visa expires. You will need to fulfill the financial requirements (400,000 THB in th bank or proof of monthly income of minimum 40,000 THB)