Personally, I prefer to do it sooner and be done with diapers. You'll hear from lots of people here who prefer a slower pace. There is nothing wrong with either decision. What times are you putting him on the potty? Right after nap or after a mealtime were good first times for us. Early morning is also great but sounds like your Ds is hanging out in the crib at that point. IIWY, I'd go ahead and let him try underwear and make the connection between peeing/wet and the potty. If you don't want to worry about messes, you can put a diaper or cloth diaper cover on over the underwear. The other key trick is to get him to sit long enough, at a time he is likely to need to pee, so that he will relax and let go. IME, it has worked best to be low pressure at first and read books, sing songs, or watch tv on the potty while sitting on the potty at the same time every day for several days in a row. We basically say, "We're going to learn how to use the potty. Let's sit here and read a few books and see what happens." A little running water in the background can be encouraging, too. We start with morning but after nap could be good too. Creating that habit of regular potty attemps, all of my kids have managed to pee in the potty within the first few days that way and it started that "A-ha" for them.
Ds1 (2006). Ds2 (2010). Ds3 (2012).