And so the circuit board looks like with one tone generator.
There are locations to mount capacitors for 6 channels, six tones.

I changed the RF oscillator from 'tuned plate tuned grid' (TPTG) in a Hartley oscillator for better efficiency, more power for same money.

The LC (coil /capacitor) sinus tone generator is a proven design of the past. I modified it slightly so I can use one generator over the whole tone range with equal amplitude for each channel by only changing capacitors. All components and connections are mounted on bottom side of the board as was often seen in the past.

Still to do,
Making the two 2 channel sticks and the casing.

TF