Serious about Sleep Advice

Ok, so I'm soliciting day time sleep advice again. Today was another frustrating day with daytime sleep. We tried letting him cry himself to sleep a couple of times this afternoon after 2 p.m. for about 10 to 15 minutes (after about a total of a little over an hour nap since 7 a.m.). He cried nonstop, and he has a very robust cry, which kind of wore on me emotionally and frazzled my nerves. We went out after awhile to try to pat him, reassure him, and guess what he did? He smiled at us really big a couple of times and started cooing away. The little bugger!!! The only thing we can conclude from this mysterious little guy is that he gets easily overstimulated. I'm trying to do the feed, awake/interact, and then sleep routine but maybe I let him stay awake too long and he gets overstimulated. He likes to look at everything Around him and seems to take so much in. When I lay him on the jungle-gym he even smiles at the "singing moving lighting up" little bird.
Anyway, all this to say that we are serious about any advice on ways to help the little man sleep during the day. As I'm writing this, he is crying away and the dear dad is trying to rock him to sleep. He got a total of only about 2 hours today since he woke up at 7 a.m. However, he does do good at nights, averages about every 4 to 5 hours and even has gone 6 and 7 hours at a time. WAAAAAHHHHH, WAAAHHHHH, WAAAAHHHHH......