well katoohla does make a pair light enough to section hike with....
and I dont have time to read this whole thread but never forget what
flying bryan used on his TC...hex head screws into the soul/tread of the boot
when he needed them; he carried the hex head screws along with a small bit drive..total weight maybe 2 ounces! he used to have a gear list up and their weights are listed.
Instep crampons are cheap and light and i used them for years, the problem for me was hitting a rock with just one spike, it torques the ankle in a bad way.