Its well worth running your designs through Noels flipper calculator, otherwise you might end up with a nice looking setup that could work so much better.
the excel spreadsheet is downloadable here:http://www.hassockshog.co.uk/flipper_calculator.htmhttp://www.hassockshog.co.uk/flipper_calculator.htm

I have used it to optimise the output of a couple of flippers, feather and heavy and its reasonably accurate