Would like Expedition to calculate TWD from a simple NEMA 0183 instrument system that doesn't have internal calibration for TWS downwind or TWA.  Question:  In Expedition TWS calibration table - should largest TWA be 180, or should it be downwind target angle for that TWS?  With B&G H3000 & H5000 it helps calibration to input the TWA at which the boat will sail downwind in addition to the TWS offset.  Thought I'd start with 10% TWS reduction at downwind target angle.  Any other thoughts for baseline starting point?  Thanks in advance for any assistance.