When you say breaks...do you mean take him out of his crib? If so, at his age i would recommend you give him at least 1hr to fall asleep during which you continue w/ your PD plan as above. Or he will soon learn: "if i don't want to sleep someone is going to let me play if i fuss long enough."
After the 1hr is up, if it were me - i would pop him in the car or stroller (if you think he will fall asleep) so he can get a catnap (30-45min). This will help in 3 ways: 1) his body will get used to sleeping in the pm 2) it will keep the cortisol levels down - cortisol will make him feel alert, when he should be tired 3) if he is overtired it will add to night waking and over tiredness.
Just my suggestions.