Well done Bob   Here is an Excel worksheet which does something similar.  It contains macros, hence it is zipped, and has some instructions on the first tab.  It evolved over time, so could be tidied up a bit, for instance with a graphic output like Bob's.   Figures are Bravo POH figures (for MTOW where applicable), and with the 50fpm decrement for prop-deice - you may need to adjust.  The wind levels selected are those on the UK Metform 214/414, so you might want to fiddle with those too.