Colin wrote:

Many years ago a highly respected aerobatic pilot in UK (still working
today) wrote an article in our Pilot magazine on this subject. He
reminded us that three things were required:
1. A rapid 180 degree change of heading.
2. Minimum loss of height.
3. Normal airspeed at the end of the manoever.
Controversially, he maintained that a highly banked slipping turn
satisfies all three criteria. The rate of decent is very high during
the turn, but the duration is so short that it results in less height
loss than either of the two alternatives (eg:slow and gentle or fast
and furious), and the airspeed is normal throughout.
Just don't forget to keep loads of top rudder on.

- Colin


I don't see why the turn should be a slipping one, you certainly will
loose more height in a slipping turn than in a normal one. And height
loss is what make the turn possible or not.