Dear Leah,
You sound like an extraordinary, fantastic mom. I think whatever you're doing is probably perfect for your son's temperament, just from the way you phrased your request.
There are different schools of thought on how much parents should emphasize attachment vs. how much they should cultivate independent exploration. But as long as his day involves some balance between face-to-face contact, independent exploration, and shared looking ("look -- a doggy!"), then the percentage of time spent in each activity probably isn't significant. You can let that fluctuate from day to day, or according to his responses.
I also think chances are very good that you've intuitively observed a social temperament in your son, and you're giving him lots of social time because that's what he responds to. That's wonderful! Just be prepared for him to have 10 million friends tromping through the house for the next 15 years or so, LOL.