We propose a novel design estimation method for adaptive streaming applications to be implemented on a partially reconfigurable FPGA. Based on experimental results we enable accurate design cost estimates at an early design stage. Given the size and computation time of a set of configurations, which can be derived through logic synthesis, our method gives estimates for configuration parameters, such as bitstream sizes, computation mid reconfiguration times. To fulfil the system's throughput requirements, the required FIFO buffer sizes are then calculated using a hybrid analysis approach based on integer linear programming and simulation. Finally, we are able to calculate the total design cost as the sum of the costs for the FPGA area, the required configuration memory and the FIFO buffers. We demonstrate our method by analysing non-obvious trade-offs for a static and dynamic implementation of adaptivity.