Do you think he is LSN? 2hrs is quite long for a 3 month old, but if that gets you the best morning nap I would stick with it. After a short nap I would try pulling it back, maybe around 1hr20. 45mins is often an UT nap, but I would be surprised if he was UT with long A times. Short naps are really common around this age though, as you found with your DD (mine too!), and there is a sleep regression around 4 months that he might be hitting early. So with that it's hard to know if it's a case of riding it out or if it can be tweaked, but I would try shorter A times towards the end of the day when he's only had catnaps.