This is what I was thought, no idea if it's correct:
Determine which side your horse is harder to bend to.
2 circles walk, 6 circles trott to the "easier" side
2 x walk, 6 x trott, 2x walk, 6 x trott "harder" side
2x walk, 6xtrott, 2xcanter to the "easier" side
2x walk, 6xtrott,2x canter, 2x walk, 6x trott, 2x canter, 2x walk
Basically, the amount of work is doubled to the "harder" side, and I do a lot of transitions.
I don't measure time as it depends on the speed of the particular horse.
I would love to hear if I'm doing it wrong.