I think the silnylon will hold up nicely, but we'll see. Seems like it's a perfect pack for you with the base weight you're carrying. I will use it for some longer trips next summer and see if I like it more. I think the Pinnacle is my favourite pack so far, but I've found out that I have a size too small, so the hipbelt is riding a bit high. Been trying to sell it here in Norway, but not much interest since few people have discovered the benefits of ul hiking yet. They're still buying big and heavy packs. In the meantime I've invested in a GG Mariposa Plus with hipbelt pockets which seems great. Can't wait to try it on the trail. Funny thing is that the G4 that I am constructing now from a kit probably will be quite similar judging from the materials I got in the kit. The silnylon is identical, even in color. Of course they're different designs, but they both come from the same range.
Btw, would you choose the thru-hiker quilt kit again if you were to make one more quilt?