I used to play a melee character in a game, and I had the buttons mapped to autorun, stop autorun, and back up. I never had to move my hands to follow a target, which greatly improved my uptime.

I think on the later mouse, with only two buttons, I retrained myself to use 'back up' to stop autorun, but it was important to me that I could mash the first button to start running and not have to worry about how many times I hit it.

Like OP said, for other apps I had it mapped to page-up/-down and back button and it made it a lot easier to focus on the code or documentation I was reading, instead of on navigating.

Thumb buttons + shift mode.

How has there not been wireless G600 yey.