Countermeasure for an inconvenience

As mentioned before, countermeasure was considered to prevent the fuel from coming into muffler through the muffler pressure line, one is setting an orifice in the line and another is make the exit point of pressure line in the fuel tank positioned much more backward in order to avoid centrifugal effect while a spinning maneuver.
The diameter of the orifice hole must be well considered, because the muffler pressure line would not be disconnected when fuel refilling, air ventilation must be done well but fuel must be prevented to flow so freely, several experimental trial would be required. This kind of researching and developing procedure should be performed by the factory manufactures, don't you think?
Their negligence of duty makes me busy, how come? My precious opinion about this inconvenience would be discerned by the factory engineer and would be reflected onto the next production, because the place I'm flying my airplane is the same as they do, their test flights.