Charles & List,
For the most part, these are academic concerns that only become practical at the statistical far edges. A wheel that is reasonably well-designed, built and stress-relieved will probably last 99% as long as one that is "perfectly" so done. But it's good to know the theory anyway.
<<4x low-flange was somehow a no-no...don't ask me why. But is there any truth to that notion at all? or just some myth I memorized long ago?>>
There is truth to it. On a 36 hole small flange hub laced 4x, every spoke WILL cross the head of the spoke next to it. This can result in spoke breakage from fretting. And when a spoke breaks, you will have to loosen two spokes to change one.
<<4x high-flange was the rage back in the 70s as I remember--or was THAT the no-no???>>
36 hole large flange laced 4x results in a spoke line almost perfectly tangent to the hub, which reduces or eliminates spoke wind-up and fretting, and thus is the best configuration for durability and stiffness. Of course, this is only an issue on rear wheels. Front wheels encounter no torsional forces, and can be laced any pattern you like from radial to 4x or other creative lacings. Other issues such as aesthetics, hub flange thickness and spoke size availability weigh more heavily in deciding a front wheel lacing pattern.
<<We all rode 3x high-flange, often double-butted, I don't remember such wheels being especially uncomfortable, especially with nice silk clements. I have a few high-flange 4x wheels in the wheel-pile, and ride them, can't say I notice much difference.>>
All other components being identical, a 4x wheel will be stiffer ONLY in torsion because of the spoke line. It probably won't be noticeable from the saddle at all, as there is no vertical stiffness difference. The 4x will last longer on the road though.
<<And 3x low-flange was a kind of de-facto standard for campagnolo-equipped bikes of the time, we all rode those a lot too.>>
32 hole small-flange 3x results in a nearly tangential spoke line also, but you need to assess rim strength and stiffness to see if a particular rider can safely use such a wheel. For a heavier or stronger rider, 36 hole small-flange 3x allows you to use more spokes to support a lightweight rim better, and without trapping adjoining spoke heads. It will have a far less tangential spoke line, but the reduced flange diameter reduces the leverage exerted on the spoke by the hub, which compensates.
<<Tires seem to be a much bigger variable in road-feel than wheel-build techniques or materials, at least in my experience.>>
True, when it comes to road feel, tires (and inflation) probably make the single biggest difference. It's all interconnected, and complicated, but spoke and rim choices often deal as much with wheel durability as ride quality.
Greg Reiche