I just got back from a NM ibex hunt. I'm 68, and that mountain kicked my butt. I used to hunt with a Rem 700 LA with 27 inch barrel. With scope and sling it weighed 10 lbs. A few years ago, I bought a Browning Mountain Ti in 7mm WSM that weighs in at 5.5 lbs. naked, and 6.5 with sling and scope. I can't imagine carrying that heavy rifle up 1600 vertical feet for ibex.
Why get an ultralight rifle and put a heavy scope on it? I shot an elk at 340 yards with a Leupold Compact 2x7 (8 oz.). At longer ranges a little more magnification would help, but I would never put a heavy scope on a light rifle. I like Leupolds because they have better eye relief, and lighter weight. The SWFA recommended above has less eye relief on low power than a Leupold has on high power.