wash the wool blankets first---they work great for battings- kind of bulky for a (birthed) method construction- but you could probably trim the wool blanket close to the stitching before turning to help cut that down- personally i would put it together (normally) - tie it if that 's the method to be used- or quilt it, which ever- then bind it.
i have a couple quilts my grandmother made 40+ years ago with wool blankets (army blankets) for batting- they have held up so well-one i keep in my car in the winter time (the just in case-emergency blanket) one side is flannel- the other side is homespuns it is great! not too heavy at all---just right---