A small update for who is interested (FWII).
I decided to modify two more servos, Simprop Tiny servos, for my system.
When something happen during a flight it can be the end of the Metz servo of post 5 and that servo is too valuable to loose. I did my first radio controlled glider attempts with that servo and later used it in my first motor plane.
The Simprop Tiny servo's are provided with switches, no slide contacts, activated by a curved wheel cut from the original potentiometer slide contact.
Weight of the radio and servos is 233 grams now. The battery of four penlights will add another 133 grams so it will be 366 grm for the cargo lifter.
All is working well now.
Next activity is field testing to adjust the tone filters and measure the range.

Taurus Tone Flyer