I love love love my mei tais. From your nursing counter I would guess your little one is close to my guys age (born 4/25/07). I've been wearing him in the mei tai since he was 7 days old. I'd suggest learning a back carry if you can, especially if you'll have some one to spot you, he loves to hang out back there and watch everything going by when I am walking with my 3 year old. He's pretty happy back there when he's not sleepy. For napping, front carries work best for us. He's able to block out more of the world when nuzzling in on me and he falls asleep much faster. He will fall asleep on my back too, but I want him to fall asleep faster I move him to the front. I think the Kozy has a pretty deep body which should mean you won't get a lot of head droop when your little one falls asleep. I am able to nurse in the mei tai by loosening the straps on the bottom and sliding my little guy down to level his head where it needed to be and then retying the bottoms. This does take practice and I was never so good I could walk around and no one would know, like other babywearing experts, but I could sit comfortably and be a little more hands free while nursing which was nice. When wearing the mei tai on the front and not wearing my little guy, I would just fold it down and tie it like a belt. Made it a little easier to use over and over and there was less strap dragging. Hope that helps some.
Ryan