It depend on the immigration. I did read that some immigrations accept only request within the last week. Its always best practise to check the local requirements first. With 70+ immigrations there are many differences.

You can wait till CM. You can extend anywhere you actually stay at that moment.

Chiang mai is strict in checking TM30. At least at the main office they are.

I would say. Start with a real visa. 60 days tourist visa. Best opion.

Follow the date on your multiple re-entry permit. Which is 26 september. Its not voided so still valid.

You need a consent letter from your wife to travel with your child: ref Thai embassy in Bern :

1.2) Only one parent travels with the child/ren; please provide

- An official relationship document, e.g., birth certificate

- consent letter* from the other parent/legal guardian with a copy of his or her passport OR if you have sole custody, you must provide a copy of custody papers OR if the other parent is deceased, you must provide a copy of the death certificate.

Get a proper visa for longstay if you intend to longstay. For some not working, studing or being retired in Thailand it means the only option is a more expensive Elite visa.

No one cares/checks about your ticket dates. Fly in before the expiration date and get your 60 days stamped.

In Chiang Mai you can apply for a extention of stay 45 days in advance.

Chris Latinoinbkk

Its not only the financial issue. For me the paece of mind knowning i can go anytime and not need to worry about getting my 2th or 3th re-entry in time made me just get the multiple. Only if i am sure its only 1 time i do a single. But nothing wrong to look at the financial side.