@Danny *********
If you want to use your "one off" visiting family extension, remember that you can only get ONE extension per Non-O visa, it's not something you can use again.
My advice: The paperwork for both the 60 day extension of stay based on visiting Thai family and the one year extension of stay based on marriage are very similar, excluding the pictures and the money requirements. If you already have the money seasoned, just get the one year extension of stay.