Ok, I think the breast is a prop for him. A general rule you can follow is that he should be able to go at least as long at night as he does in the day. So if he is consistently lasting 4hr in the day, you would resettle each waking that starts before 4hr has passed since the last feed. Its important though, that if he's awake and you're in the middle of resettling and the 4hr mark is reached, you have to get him to sleep before you feed him, even if its only for 10mins - that way you're not reinforcing that if he cries long enough, you'll feed him.
At 6.5 months, LO's may still need 1-2 NF's.
One other thing - have the night wakings become worse since you started solids?