Gotta love the power of the placebo effect.

There is NO way that 'heels down' will give you some magical power boost that's significant. It may help you shift briefly to other muscles, but it will likely yield no statistically significant time decrease if you actually tested it over and over again.

The laws of physics are against you here.

Having climbed many, many hills and having timed my climbs on lots of them, on a TT bike, road bike, standing, sitting, triple gearing, standard gearing, the one take away message is - be in better shape to go faster. All the rest is BS, just as physics predicts.

You don't even have to ride big hills to get better at them - just put out lots of watts during training, either on the flats or the trainer.