How many loads can CCLK drive? In a daisy chained application, there could be multiple PROMs and FPGAs driven by a single CCLK.
The rule of thumb is 8 loads maximum on a single CCLK. A separate driver might be necessary for more than 8 loads. In addition, the faster the configuration rate is, the greater the possibility a driver will be needed for multiple loads.
An alternative would be to break up one long configuration chain into two(or more) smaller chains so there will be multiple Masters. This will effectively reduce the load on CCLK.