We switched to the overnight disposables at about 4 months and she has been leaking out of them recently at 12 months. I put a fleece cover over them just so she isn't soaked everywhere.
It's ridiculous, I feel so guilty but she sleeps through the night and I don't have the courage to wake and change her.
Last night I put a Thirsties hemp prefold in a bamboozle, covered it with a Thirsties duo and a fleece soaker, it was soaked in the morning but her pjs were dry. So I am hoping this will work for us.
Good luck to you and do what works for your family.