Yours is rather an unusual case I suspect, if it was solely to highlight the potential pitfalls in repatriating money then perhaps the topic title needn't have references your visa.
I think the vast majority of those on a non O marriage extension bring the money over and either leave it on deposit, or spend it through the year. Unless you're very lucky with favourable fluctuations in exchange rate you'll simple lose money coming in and lose money going out.
As for knowing the future I would presume, seeing as your original post stated an intention to make Thailand your home, you're going to have to go through this rigmarole again in 12 months which strikes me, personally, as plain bonkers. But each to their own, I would suggest you try Dee Money to repatriate your money.
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