I have an excell spreadsheet (
http://www.the-hardings.org/the-hard...rg/vfrplan.xlt) it uses macros just adjust the gph for your plane.
Also I have a w/b for my 182 should be easy to change (go to the second page for table of the graph and enter your own CoG figures)
http://www.the-hardings.org/the-hardings.org/wb_182.xlt
Cheers