At the moment, I cannot provide the exact date of when the MH620 will arrive on site. I will know once it has arrived at the port and we have all the shipping document ready for custom clearance. However, I have already let Subhasis know of the estimated date for your technicians to come. That is on the 8th August 2016. I will let you know again once I have a confirmation.
As for the visa, since your technicians will be staying with us for 6 consecutive weeks, I believe they will require a business visa. I can provide you with letter of invitation for use when applying visa if needed. You should check with the Thai Embassy and begin preparing for the applications.