Based on what I have seen with the CiES design and installation, changing the float arm geometry would not be a problem as the sensor and display are calibrated together with fuel after the sensor is installed. Much like I believe Dynon and Garmin do now.
Here is the old thread on the sensors.
http://www.vansairforce.com/communit...highlight=Cies
I believe that on issue is the problem of measuring the fuel at the top of the tank. It appears that this issue that is solved in other aircraft with the installation of an inboard and outboard sensor in each tank that are tied together electrically. It looks like the extra work and expense involved my be an issue for many builders that have never trusted the fuel level indicating systems in their aircraft anyway.
It's good technology, provides very repeatable and accurate information if installed and calibrated properly.
Here is a whitepaper that appears to describe the problem with measuring the furl in the top of the tank.
http://fuellevel.blogspot.com/2013/0...el-sensor.html
I would like to hear what you find out from CiES.
-larosta
Yes accurate and reliable fuel level measurements are an interest of mine.