Abgd,
No need to lower the nose PRIOR to uncrossing the controls It works like this.
As you enter the slip the nose will have a shallower angle. You maintain this pitch angle. The ASI will show a lower speed due to position error. As you straighten up the nose 'falls' back to the original pitch angle and the indicated speed on the ASI is restored. It never actually changed.
Slam,
Choosing a higher than normal approach speed just leaves you in ground effect with excess speed which makes the whole thing pointless. Don't see what's wrong with doing it at the proper speed.
The whole point of the exercise being to increase the drag to increase the descent angle.