Not Cowboy, they won't let me play him on TV, but this is how I think of it...
Picture a clock with heat at noon and 21 days going around.
For the first 5 or so days after heat (day 0) there is no functional CL so lutalyse won't work (that takes you to about 3 oclock); from 3 oclock to 9 oclock lutalyse will work; from 9 to noon lutalyse could work but you don't really need it because the cow will come into heat on her own.
So you want to put your CIDR in so you can pull it after day 7(that would be about 4:30!) - so I would work backward from when someone will be around to breed the cows - does that make any sense?In essance since you know when they were in heat you are one step ahead.
Cowboy might have something more erudite to say...