It is easy to do online, so why not try that about 8 days before the due date. If it is not approved within a week you can then go to the IO in person.
I have had no problems with the online system, but I know others have.
I managed to open one 2 years ago, but I am seeing a lot of posts saying that it has changed now. Definitely give it a try, ask the bank what they require first. You might need to try several banks before you find one that is willing.
I tried many banks and different branches before being successful at the Bangkok Bank.
The agent fee for this task seems to be about 4 to 5,000 Baht if you need to. Everything else with the visa process is simply providing the evidence requested by immigration and attending on the correct dates, so need for an agent for that.
that explains it. The visa part at the immigration office is the easy part. Everything for registering the marriage involves a couple of visits to the different places, chugging around Bkk and appointments to be made, often weeks in advance. I must admit if I did it again (I won't) I would pay an agent to do more of the legwork, but you navigated it perfectly 👏
this is a great explanation of the process and your experience. You make it seem very simple, but I think you did really well to cram all that into the 60 days. I presume you and your wife were based in Bangkok for the 60 days.