The stands look very sturdy indeed! In reference, what Turkey call 'donkeys' we call 'sawhorses'.
Ovened wood is also called kiln-dried and should be left in open air for a few days to adjust to your climate and humidity. If it begins to warp or twist, better then than after you've installed it.
One note about placement of the propane tank; it also needs venting. Propane is heavier than air so vent holes in the bottom of the compartment will work.
I also will be watching your build with interest; always good to learn of other cultures and methods.