Also watch the A times hun. It looks like at some A times it's a little long, given it's only been a 45min nap. At your lo's age, about an 1hr15min is the max time to be up, and if he has a short nap, then I would only keep him up maybe an hour. The first A time of the day is also the shortest as it's kind of a continuation of the night time sleep, and also the easiest to get them to go to sleep and sleep longer. so if you put him down at the hour mark for the first A time, he may sleep a little longer, then he can stay up for the 1hr15m mark for the next one. If he's having lots of 45mins, you will find by the end of the day a very tired LO.
Good luck, and keep up the good work!