I have the Sigma Scout 150-600 attached to a Nikon D800 and use the Black Rapid shoulder strap attached to the tripod bracket and let the lens and camera hang down on my right side. I can instantly slide up for quick shots. Works fine for shorter hikes through the swamp areas shooting water birds. I use this arrangement for 3-4 mile hikes on the berms of Black Bear Wilderness here in Seminole County Florida without a tripod (hand held).
ON1 Version 10 is great! allows you to do everything from photo organization to layers. I have been using their products since about version 6. Problems... sometimes with new releases but they are fixed quickly. Also, and very important, they have the best training videos and webinars in the industry.
At least look at "Black Rapid". I have been using Black Rapid with my Nikon D600 & D800 for several years without a problem. Works very well for hiking and, sometimes, biking.