If anyone needs new fuel floats, you may have another more accurate option.  The CiES website indicates that their floats may now be used on certified aircraft other than Cirrus.  They apparently have already got it approved for Cessna 177/177RG.  The price for those sensors is $385/sensor and can be used with a JPI930 or Aerospace Logic indicators (which cost about $600).   The first set takes some time as CiES uses an old set of floats, makes measurements, tests, etc.  The idea of combining