Running

do you mean 1.20 rest after the sub 4 minute K?
if you do thats plenty
you need to able to bang out 8 smooth sub4 min ks,
the first in a race youll be rushing, and the last will be bang out to finish,
suggest using a stopwatch and nailing 8 sub 4 min ks, strict distance, very short break then kick

I was doing 1km efforts, followed by 1km of 'rest' periods. I was planning on trying to reduce the rest distance to .5km, and then to slowly try to increase the pace distances by .5 increments.