Great topic, great read! Thanks SEA Traveller for posting it all.
So what's the size of the plot? Is it indeed 100 square wa or is it actually a rai? I'm a bit lost in strange units like square feet or meters. I noted that you said someone was correct in highlighting that the units to match up but then you didn't say which it was, if the sq. meter number was incorrect or the Thai unit?
Secondly: That's a major wall!
My question is: Why? Is this going to be a gated, managed development, or is it pretty much open in that the owner divided up some plots, is selling them and will end his involvement there? I think the wall is very high and I'm not quite sure why it's needed.. please enlighten me, it's one of the few things I don't yet 'get' in Thailand.
In my development all plots have a concrete lining around them that's less than a foot high, with posts every x meters to put lights or flower pots or whatever, and then metal fencing that's still not very high, about a meter I guess. As a result the whole area looks very open friendly. ( Then of course on the OUTSIDE perimiter wall of the gated community there's fortress walls, a crocodile infested moat, gun turrets and all that jazz.
)
One advantage that I could see to a proper wall like you have is that it would keep cats out... But then you're looking at this concrete wall all the time so I'm not sure I wouldn't rather have the occasional cat-visit.