Thanks, Roger, for your thoughts. That clears up a lot. We have posted about wind shift; but I’ve found that 180 degree shifts are extremely rare where I’ve hiked; although suppose there are instances where they do occur. Having tents with vents that are well protected, I button the doors up before bed in case of storms. I did use an unbuttonable tent for a few years. Great space and ventilation, but not for above timberline or other unprotected areas:

After posting, and from Nick’s comments about “nightmare” sand, there came a thought that for some extreme conditions, a light construction mask might be carried. I’ve always had a plastic particle mask for cutting fiberglass, carbon fiber and such (note: no good for covid-the intake filter is great, but what you breath out is not filtered). There are check valves on the exhale ports, and there is no leakage of air around the mask. This might help for severe blowing sand; but then, goggles would be needed also.
D-bag, it sounds like your experiences with tents have been problematic. For ages, I’ve modified tents to remove glitches; so have had almost zero troubles. It helps to start with a good tent; but this Eureka cheapy was very tough to modify. After many years, it started leaking at the peak during torrential rains, and no amount of patching or sealing would fix it. Probably, the fabric coating just wore out:

It was a good tent, though, for a long time, and had a dry pitch; that is, the inner tent was built in, so no rain entered when pitching it. The tents since have been good ones, but are more conventional, and the inner tent must go up first before the fly is attached, often with flooding of the bathtub floor in downpours. Which gave rise to the desire to build a new tent from scratch, using the lightest materials other than DCF, which I’m not sold on and is very expensive (have big doubts whether a DCF tent would last many years). And that is why I’m forever asking about tent design. Don’t want to leave something important out until after the tent is completed and sealed. Did that with a pack that now needs major modifications, and may have to restart from scratch.