No experience with the Spider system, but I have the same camera and use the Peak Design Capture Clip.
I put it on my packs' shoulder straps and generally like it. Has always stayed secure, even when skiing, and the shoulder strap placement generally keeps it out of the way when bushwhacking.
Main complaints are that it does strain my shoulder a bit over a full day, particularly if I have my biggest 100-400 lens on the body. And I wish their Standard Plate had anti-rotation pins in addition to the 1/4-20 screw; as is, it has a tendency to rotate on a tripod, particularly when shooting vertical and/or with my biggest lens.