Apply for 90 day non o visa in home country when you get here go to immigration and get a residency certificate and ask for a letter for the bank to open the account
Get a non o visa for 3 months get to thailand and get a residency certificate then go to immigration and get a letter for the bank marry the girl and put
*****
0 baht in the bank and you will then apply for marriage visa
Visa agents are not necessary if you arrive with a non o visa and file a residency certificate you can get a letter from immigration to open a bank account