The Kumo is a nice comfortable pack. But, you will likely need to upgrade the sitpad to a nightlight pad. It makes a big difference in carrying capacity and comfort.
The new version is also 18.5oz. The added NightLite will add about 3-4oz more for an additional 10 pounds of capacity.
Personally, I would have gotten the new Murmur. You can use the nightlite for an additional 10 pounds of capacity on it, also. According to the specs on the new version (I have an older 2015 version) it is about 1.5″ thicker at 6″ deep. This is ideal for handling stuff sacks. Both my Miniposa and older Murmur have ripped out the sides(repaired) where I put in an 7″ drybag for my sleeping gear. Of course, you can use the pad for sleeping or as a sitlite pad, even though I also carry a NeoAir. The two work well together in early spring/late fall for warmth. I don’t care too much for the angled front pouch on the Kumo. This is just a style gimmick… When I stop in town for resupply, I often just stuff it in the front pouch and go, not bothering to load stuff where it goes. I can do that at camp, later. Anyway, the Murmur would have saved about 5oz, overall. Both have thin padding and wider shoulder straps than most others making them easy to carry. The hip belts are also minimally padded and easily support 60-70% of the pack. I often loosen the shoulder straps on a hot day and let the pack drop off my back…it is a bit cooler. In summer months, I use the Nightlite as a pillow, stuffed into a stuff sack. Anyway, both are good packs for UL travel. The Kumo has a bit of an edge with durability, the Murmur has a bit of an edge with weight. After 25 years of going UL, flirting with SUL, I still think than any UltraLight pack should NOT weigh more than 16oz or one pound. After a couple outings, you can strip off any additional strapping, plastic, elastic, etc to save an additional ounce or so. The top closure on the Kumo doesn’t really need much in the way of compression. The Roll top on the Murmur is about the same way, but a different style.