What are the requirements and application process for the O visa for US passport holders over 50 in Thailand?

Hi. Hoping to get clarification. US passport holder over 50 years old. I know the O-A visa application is done in the US and can get up to 2 years stay without any banked money in Thailand.

Is the O visa still available to apply for in Thailand at all IMM offices? This is the visa requiring the 800,00 baht funds in a Thai Bank for 60 days before applying and must not go below 400,000 until after issued for 3 months? Is this a 1 year multi entry visa which is then renewed every year? Do the funds used to open the bank account need to transferred from overseas or can the deposit be made in Thailand? Any other requirements to get this visa?

For ease of issuance, I am willing to bank the funds and not rely on monthly transfers. My history is always on visa exempt entries, usually for less than 30 days each stay, 3 to 4 times a year. I now know I need to get a visa and want to know if the O visa would meet my needs. Thanks for any advice.