The DTV Visa is activated upon acceptance by the consulate you apply through.  Given the period of time for processing being on average 6 to 8 days I would be doing the application about 2-3 weeks prior to your requirement for it as to not waste a month or two of the Visa period.
Yes get a PDF creator app and create one document. You may need to make it black and white to reduce the file size. From memory they can not be larger than 3MB. As mentioned above wait to hear from them now. I called the Thai embassy to discuss my application in Aust and my supporting documents. They were very helpful. My application was approved. 24 hours later.