In my area the good fall flow is the key to a successful overwintering, big colonies and small.
If you constantly don't have any good fall flows you should reconsider to change the area you are keeping those colonies and the size the colonies you are overwintering, not necessarily 5 frame nucs but 10 frames. Also adjust the time and size you make those summer splits.
The whole idea is to have those summer splits to grow and be as self sustained as possible.