1. Tanned hides seem to be better from any sort of cloth. In old DF leather had assigned defensive value 1, while metal had value 2-3 and cloth had value 0. Now, DF is sorting this out by material values. Still for many purposes in the game leather, shell and bones better protect from damage then plain cloths. Someone can dig for those numbers to show how exactly better bone/shell/leather armor and cloths are from woolen, silk and plant cloths.
2. Tanned hides do not get master quality issue from tanning and have no dying, so judging if used leather cloths are fit for destruction or for sale to merchant is done merely by observing their basic quality. You do not need to read their description for hints, which makes whole process of sorting cloths out faster and easier.
3. Obtaining hides can be an issue. Even 10 hunters won't do you much good in some shell-animals biomes. Bringing own animals for furs seems the best solutions. I was fond of alpacas, which drops you bones, skulls, wool and hide. However, I am considering now dogs for tanned hides production, as I always bring dog couple on embark. Some silk thread and wool yarn for artifacts you can always buy from 1st caravan. Gems too btw. All you need is just 10-20 wheelbarrows for sale and you are set for your artifact production needs.
4. To get all artifacts in adamantine, you need to move adamantine above iron in inorganic materials file, before creating new world. Also you can delete those waffles from it, so you get more use of this material. Second thing is to observe when moody Dwarf starts project, that there is more materials involved in making artifact then the base one. If there are more then just forbid base material. Artifact in 4-5 days will turn out to be out of adamantine. If there are just the base material, like for example 3 logs, then nothing can be done about it. Forbidding 2 out of 3 logs won't change artifact material and forbidding base material in its entirety will make Dwarf going mad after whole month. Issue with adamantine cloths is, no Dwarf will be using it. You will have to assign it as part of uniform for soldiers/militia. Civilians will have to do with non-artifact cloths all the way.
From my point of view, I wasn't much bothered with cloths before. Made some only when naked kids couldn't get feet, legs and torso covered with what was in store. I cared only for leather armor. However on my last embark I removed waffles from adamantine and making adamantine armor proved no hassle at all. I got heap of unused hides. Managing disposal of used cloths is producing some issues. You can't destroy master quality items easily, so I moved into leather cloths.
Careful management in clothing industry of giant cave spider silk cloth however can lead to high value silk rope and silk bags, which can add to fortress architecture value. I am yet still to capture giant cave spider for a silk farm on my last embark. So this industry can prove still its worth. You can decorate bags and ropes with adamantine and other metals. There is no limit for encrusting, so long material does not repeat itself. Only issue is, that non-master quality encrusting can not be removed from item, which is sad state of this affair. On the bonus side, game is no longer tracking item used for encrusting, so it has a positive impact on fps.