Are you doing a dreamfeed? That's a great way to get a few extra ounces into him to make sure he isn't getting hungry during the night. You don't have to wake him fully for a dreamfeed, just enough so that he eats a little, then straight back to bed. At his age, he can be happy eating anywhere from 26-38 oz, so it looks like he's right in the middle.
I really wouldn't recommend starting solids at 3.5 mo for many reasons. Most experts agree that solids should be introduced between 4-6 mo. There are many signs of readiness to look for when determining when to start solids. This link might be of some help:
http://www.babywhisperer.com/forum/is-your-baby-ready-for-solids-vt36922.htmlIt sounds like you've got a good thing going now, and if it isn't broke, it may be best not to fix it! If he's hungry, he'll let you know!
