Others here can give you specifics but, basically, there is no set number of points (like in the Concierge Collection). An exchange is arranged by Member Services and they negotiate the rate. Usually these have to be weekly exchanges. Figure it will cost at least a full week in a one-bedroom.
Depending on your Use month, keep track of when those extra points will be expiring. You may take a non-
DVC trip during the last 60 days of your Use Year but you may not call to make the reservation for a non-DVC trip that late into the year.