He did at the seminar I attended as follows
600m breakdown
600 walk 600
500 walk 500
400 walk 400
300 walk 300
200 walk 200
100 walk 100
I did it a few times but personally didn’t like it that much and switched to
100
200
300
400
400
300
200
100
all with 1 min rec
with tempo you can get pretty creative CF talked about doing Long tempo as split runs
300
500
600
500
300
IMHO the key thing is to do what works for you and means that you will do it.