I don’t. As you’ve observed, it is nearly (and practically) impossible to duplicate a complex analog patch, even with a detailed patch diagram.
With my LZX Modular, I find it more beneficial to document the TECHNIQUE that gets you certain outputs, and not the exact patch. This way you will build up a library of ‘chops’ that you can combine and rearrange for desired outcomes.
For a very simple example, “processed/cross-faded vertical ramps into FM inputs of 2 oscillators, output of one oscillator modulates gain of second osc, sine outputs of both OSC into logic processor generates shapes varied by processor controls”
In practice I don’t usually make notations or pictures, I just work with the patch long enough to explore the outcomes it can produce. My approach is to build up ‘muscle memory’ for patch techniques.
The only way to preserve a patch is not to pull it - but even this isn’t a guarantee of repeatability due to the nature of analog circuits and environmental conditions.