I briefly played with Co-Pilot 2-3 years ago, on a PDA. It kind of worked; it was one of quite a number of USA-centric applications which do the usual stuff; wind calcs, W&B, and with a bit of luck they might contain some European waypoints so you can do a simple route plan. Since DAFIF closed to the public in 2006, most of the cheap/free American flight planning progs dropped support for Europe.
Eventually I gave up with PDAs but continued to keep a PDA program which does a nice graphical W&B, because I had to demonstrate a W&B calc for the FAA CPL checkride. Never used it since, as there is no practical way (using human cargo) to load the TB20 outside the envelope, without exceeding MTOW.
I am sure a nice little graphical W&B program, running on a modern phone, would be very good for the many pilots whose aircraft can be overloaded fore/aft.
It is not readily apparent from the website whether CoPilot does a graphical W&B.