How fast should the techniques be done?  It really doesn't matter how fast one does any of the techniques.  What matters most is that the tempo of the techniques be kept the same.  What I mean by this is that the techniques shouldn't start out slow and end fast or vice versa.  The technique should have a smooth flow with the same tempo throughout the entire movement. Some say that your movement should match the speed of your partners.  I am not in favor of that.  Younger people are naturally faster than older people.  It is just human nature.  If we try and keep up with them, we will succumb to their speed.  Furuya Sensei used to say, "Bring the other person into your movement.  Don't let them bring you into theirs."  So by that aphorism one shouldn't try and match the speed of their opponent.

The techniques should also only be done as fast as one can do them correctly or in other words being able to maintain the proper body position, balance and posture while making sure to execute every step of the technique.  Experts follow the same steps as beginners but they just do them faster.

When one is a beginner, they should try and do the techniques slower so that all the steps are followed.  The adage, "If you can't do it slow, you can't do it fast" is something I have heard numerous teacher say in one way or another.

Keep the same tempo and only do the techniques as fast as one can still give each step is proper emphasis.  Once you master the steps, speed up, but not until then.