my wind down is also about 5-10 minutes : go up to room, turn on white noise, say "night-night" to favorite objects around room (sort of tells him it's time for nap), put paci in mouth, sit in rocker and sing 2 verses of song, swaddle, then into bed. He usually fusses a little at the swaddle, but by the time it's finished he's half asleep, and by the time he's tucked in fully asleep.
Even though our wind down is pretty short, I've found that in the last 10 minutes before we go up for our nap, I try to have quiet activity rather than light-music toys going on. So, we'll play with soft toys, sing a song, do hand play, read a book etc. But he won't play in his exercauser, gym, etc. He needs some transition time between play and wind down. The more transition he has, the less "jolting" I see at the 45 minute mark, and the less jolting he does, the more likely he is to put himself back to sleep rather than wake up with a full-on cry. He'll almost always still wake up at the 45 minute mark - I think that's a natural time for him to come out of REM sleep - but sometimes all I hear is a light murmer and then he goes right back to sleep.
I also want to say that now that he's 5 months, he gets REALLY mad if the wind down isn't exactly the same every time! And if "A" time wasn't long enough, he'll get super agitated when I start wind down, because he's not ready for sleep! So he knows what wind down means!