Sure, Ed, I have a couple of thoughts. One is that even with a big load like youre packing, todays boots offer a lot of support with less weight than was needed ten to 12 years ago. The other is that you are on the right track.
The ViozI like both the boots you are looking at. The Vioz ($250) is a lovely pair of bootsbuilt like a Hummer, one-piece leather uppers, Gore-Tex inner booties, polyurethane midsole. Very tough boots. The SL M3s ($210) are excellent as well, a little more old-style, without Gore-Tex inner booties, which is not a bad thing, as it results in a slightly more breathable boot. Full-grain leather uppers, tough midsole, very good boots. I also really like Scarpas Escape ($269), which are more of a light mountaineering boot, but very suitable for tough backpacking.
There are other solid candidates out there. I often wear Asolo boots, and s Power Matic 200 GV ($270) is another iteration of the tough, heavy-duty backpacking boot you are after. Full-grain leather outers, Gore-Tex bootie, polyurethane sole, a lot like the Vioz. And there is the Contact ($240), which sports an inner bootie of eVent, an excellent waterproof-breathable fabric. Ive been wearing Contacts on weekly hikes of Tiger Mountain, outside of Seattle, and have found them to be very supportive, comfortable, and tough.
What matters, though, is what fits. So try to find a place where you can put on at least two of these boots. Three is better. Theyre all good, so just get the ones that feel the best.