Thank you for your reply.
Yes, I followed your tests closely. Thank you for all the helpful work you did with them. Alas, T-H has only quite darker colors, along with the bright orange-yellow that I was referring to.
Yes, that is a great store. Not sure if Rainshed's were among the many tested, but am pretty sure the Skylite and Ultrasil are Westmark products, that have been tested and are OK, but nothing close to the Thru-Hiker "Shield" silnyons in terms of water resistance. Maybe I will order a bit of the Ultrasil, though, and see how it's doing these days (they have it in a sand color). You never can tell - thank you.
What is good about T-H's 'Shield' silnylon is that it is not only much more water resistant; but it also sags less than the others when cold and humidity increase. In falling temperatures in the rain, not unusual for backpackers especially in the shoulder seasons, I have observed silnylon to "mist" up heavily (including dripping) on the inside even when highly vented with no one under it, and expand so that it sags. This happened even when half of the canopy was shielded from the rain, and even when the HH was in the 3500mm range (not from T-H). And surprisingly, there was more mist under the shielded side than the side exposed to the rain. So, I don't think the mist is attributable to leakage, but whether it is or not, I would not want to spend the night under such a soaking wet canopy without a protective liner of some kind.
By sagging less, the higher quality coat silnylon will work better with less contact with a netting inner, and if indeed the 'mist' is partly from penetration, allow less of that from which drops can roll off. The most I hope to accomplish with the higher quality silnylon is to achieve a tauter canopy with both elasticity and substantially reduced sag, and to sew strong lap or flat felled seams without a lot of the gluing, bonding, clamping and tighter allowances that go with Cuben. That might be doable for many with a tarp; but with all the seams required for a tent, it is probably a recipe for MYOG madness, and IMO, certainly not an appealing project for those who visit this forum.