Chesterella, as a rule of thumb, at that age I was working on set morning nap time and A times in the afternoon.
For example, I would give my dd a nap around 9am in the morning (she would wake anywhere from 5.30-6am) and let her nap for 45mins. Then I would do the afternoon nap around 3.25hrs later.. so that she would be asleep by 3.5hrs A time.
So in your case, you said he took a morning nap at 9.30am (which would have ended at 10:"15am) and then you tried for a nap around 12.30 and did pu/pd for an hour. Well I think he was probably NOT tired enough for a nap around 12.30 because on a 45min nap, he would have been able to stay awake for about 3hrs.
So try to aim for something like this:
7am - wake
10ish - morning nap (wake him up 45mins into the nap)
10:45ish - morning nap ends
2pm - afternoon nap
3.30pm - nap ends
7pm - bedtime
There is no point trying for an earlier bedtime if his pm nap ends at 5pm.... he is just not going to be tired enough at 6-6.30pm and if he does fall asleep then you'll get nightwakings. A nap too late into the afternoon can also cause nightwakings. Try not to have him take the pm nap any later than 4pm.
Let me know how things are going
Layla