it takes maybe 10 minutes at the most to answer the OPs post, with just the needed details. It's also not good to whine about not being able to promote your blog...lolol
the time frame all depends on what country you are in when you apply. In Vietnam you can face a six month time frame, yet in Taiwan it is just 30 days. It all depends on where you apply. What Thai embassy/consulate are you going to apply at?
buying a tourist visa is no guarantee you'll be let in. If you are tagged as trying to stay long term on tourist entries, buying a tourist visa isn't going to change getting refused entry. You'll need a long term visa extension, not a tourist visa.
Never forget that immigration profiles, and stereotypes people. If you fit their profile they make it hard, or refuse entry, but with the DTV, which is a tourist visa, they can make you show an exit ticket, in keeping with rules, instead of overlooking them.
Be fully aware that for the extension you need to produce all the updated documents you used to originally get the DTV. By leaving and immediately returning you don't have to produce any documents other than your DTV printed out.