How Long Do You Feed in the Fall

[Two Bees]

Have fed both hives two gallons of medicated 2:1 syrup (Fumagilin-B) and a third gallon of plain 2:1 syrup.  In central NC, we have started getting some frosty nights in the past couple of weeks.  How long should I feed before I button the hives up for the winter?  As long as they will take it?

[BEES4U]

FYI:
The winter weight is put on the bees 1st and the Fumagillin is fed 2nd so that the bees are medicated at the time of feeding. This method makes the bees use the medicated syrup that is stored in the proximity of the wintering cluster 1st.
Each climatic zone requires a different weight.
Maybe some one can post your feeding question that is near you.
Regards,
Ernie