If you cut the inch off all the way around, that will make it just the size of the top. The quilt might 'take up' a bit in quilting and so having the backing exactly the same size might be an issue (if you are having it long armed, it will really be an issue). I think I'd just go with a different backing.
Plan "B" would be to cut 2" off all the way around. This would make it half the size of the block and give you enough over so you could use the fleece.