Top three is pretty rarified turf. If you're "you're just nursing it along in the top three" that says a lot about your basic skill set!
Desert racers routinely run 90 to 120+ miles at 80% - 90% race pace with no tachs. Some open jeep road sections are 80 MPH or better on knobbies for a few miles. Fast guys will always go fast, I've found. A skilled, disciplined rider that has some mechanical sympathy has a far better chance of finishing, & placing/winning in an endurance event than a "wildcat" rider. Undisciplined wild riders can break anything, either by crashing or mechanical abuse.
A tach informs you but doesn't affect your skill level. A tach can obviously be a great tool if you are routinely "pushing it" to redline levels to maximize HP & acceleration, but my point was that if you have
plenty of HP on tap (Hayabusa/ZX14) you are likely
not going to be glued to the redline looking for more. Spending the engine's service life at redline shortens that life, and as speed generally equals HP, going fast on a higher HP machine is easier on the engine. Maybe not so much for the tires, brakes & rider, but with real HP on tap the engine doesn't need to work at maximum effort nearly as much. On a track where everyone's likely on the same displacement level, high RPMs are a forgone conclusion. On the street, unless you have the "deep pockets" for regular rebuilds, more cubes is probably a better long term solution than continuous high RPM.