The filter sweep as set by the start & stop frequency controls is always the same once triggered, no matter how hard a string is plucked.

Looking at the circuit of Rev 1 drawn 28 September 1996, what if the peak follower output at junction of D3 and pin 6 of IC5B, which the circuit states falls between 0v and -7v depending on signal, is connected to one side of a 10k pot, and the voltage at the wiper of the Start Frequency to the other side, with its wiper connected to R93 and on to the CA3094? The Start Frequency pot is also connected to 0v and -V so this should not present any problem.

Depending on the setting of the additional 10k pot, could this make the initial peak of the filter sweep follow input level?