my DS is also textbook
when he was younger, i used to do windown 30 mins prior to nap as well. i wait till his first yawn, then put him to bed. he would usually be asleep within 10 mins (max. 20 mins).
mind you, when DS is older his sleep cue start fading, it got a little trickier to when to put him to bed.
good news is, DS is now 7 months. i don't need to do windown. when it's time to bed, i just pop him to his cot and he will do it all by himself
and yeah, i feel absolutely amazed that DS fall asleep, wake up, get hungry ..precisely on the clock !