Overpower's range is barely half of Tomahawk. Its technically impossible to pull with since you will always facepull first like a scrub.
I'd actually strongly recommend against this in fact, as in a controlled fight your DPS/healers will go caveman as soon as they see you hit a Tomahawk, and generally be safe, if they try and do the same while you mosey into Overpower range you're losing seconds of DPS uptime and can potentially end up with the boss yo-yoing into a suboptimal position.
Not a habit I'd recommend getting into.
Running up to the boss and pulling in general is pretty sloppy and suboptimal, actually. All of the de facto ranged tank pulling abilities (Shield Lob, Tomahawk, Unmend) have a 15y range which means you can get within range to use these abilities on any boss without actually pulling them. Doing this before a pull and then hitting the button from a standing position and THEN running to the boss allows your DPS to immediately go to town without any worry of face-aggro. If you run up to the boss even if you're mashing the button, the attack will not register on the boss until after you have already facepulled, and if any of your DPS have started their openers in that period you're putting the pull at a disadvantage.