My annual Visa expires 1th July. (non immigrant b)
I have a flight out of Thailand 5 July.
Two questions:

1. Submission prior to expiration date
   How many days/months prior to VISA expiration date(1 July) is it possible to submit all documents to immigration? As it normally takes in my case a few weeks to get extension granted.
   Normally I submitted all documents at expiration day, which i cant make my flight.
2. Extension
   Would it be possible to extend current expiration (1th July) 1 or 2 months and then complete the process upon return?

1. You can apply up to 30 days early or 45 days at some offices.

2, No

Non Imm ‘O’ At JW Bangkok 45 days in advance. I believe the internet says two months. I renewed my Retirement on 3rd March it expires on April 9th