Very exciting building your first home here in Thailand where there is freedom to do many things. Since the house was built I have done so many things that back in the US would had been almost impossible and certainly costly , what with submitting plans , getting permits, having everything signed off by licence tradesman etc.
We also did the double wall 7.5 Q-con on all the outside walls ,
and we are glad we did. House is nice and cool, and our electric bills are reasonable.
And you dont see the columns.
Make sure they build a bottom beam a top beam and side columns by the windows. as shown on the second picture,
Also when they cut the grooves on the Q-con,to run the electric, make sure that when they patch it up , they put wire lath (screen) over the grooves they cut to prevent hairline cracks showing up later on. I was not there when they did the rendering on the walls, and now i see a small hairline crack leading from the electric outlets. I can tell exactly where they run the lines. I suspect they did not tape the grooves with wire screen. When I did another bedroom extension later on ,I insisted on taping the grooves with wire screen, and I don't even have one crack on the walls.
excuse me for repeating things that you might already know, but I don't know what you don't know, so better to be safe than sorry