Wind can be tricky. I live in Boulder, CO, and strong wind a is pretty common thing. I don't have it all figured out yet, and so far I've only done location shooting with speedlights and medium sized umbrellas, but I've figured a few things out. I come from an outdoor adventure background, and I've been able to find a few answers there. Sandbags have no replacement, and should definately be used when you're shooting with that kind of equipment. You've got a $1000 octa, with I don't know what kind of head, but do you want to take any kind of chance with that equipment, let alone the safety of your models. Where I am, even on a completely calm day, the wind can kick up at anytime, and it does no good to put sand on your stand afer they all get blown over. One thing I've found that I keep in my bag, is a super lightweight sil-nylon stuff sack that you can find at any outdoor sporting goods store like REI or EMS. It's like a sand bag without the sand. Since I do alot of shooting in the field that involves hiking first, I'm sure not going to carry 20 pounds of sand in my pack, but I can carry one ofr those for less than an ounce, and I can almost always find somethingto fill with with when I get there (sand, dirt, pebbles, snow...). Another thing is to buy some spare guyline cord from a tent, which is only about 3mm thick, but has a test strngth of about 100 pounds; so it's really small and light, but plenty strong enough to secure lights. Then get a few each of different kind of tent pegs, and you can also secure things that way. As for your question about both, I find that works very well. Enough sand will hold anything down, but what you run into is that the base of your stand is secure, but your light is 9 feet in the air, and it's still all over the place, swaying around like crazy, and you still feel like even if your stand stays put, everything on it might still snap off. So, I'll sometimes use sand for the base, and run three guylines up to somewhere near the top of the stand, to provide upper stability. Works pretty well.
As for the ankle weight idea, that is totally brilliant! I never thought of it either.