The Debayering matrix setup you choose for the Hypercam 26C (like any camera) depends on your particular processing and capture software. In most cases, either RGGB or GBRG seems to work.

Please note that the row order can be inverted by the capture and processing software when the debayering information is read and applied to the RAW .FITS or .SER image.

To learn more about Debayering, and why combinations vary with processing and capture software, please read this article about Debayering your CMOS camera.