To swap waveforms is useful ( in contact mode) when you are using a waveform with only possitive (or negative) part, as when you use a 100% offset, or when you use a waveform with the offset already integrated.
If you use a plain sine waveform or a square wave, with 0% offset, then no need to swap waveforms, as the polarities are swapped at the rithm of the freq you are receiving, and thus, no acid buildup.
You are going to find a lot of different ways to set up a session, as all of this is experimental. However, the only presets that are written on stone are the Spooky Central (plasma), Spooky Scalar, and the cold laser one, as an incorrect setting could damage the devices.
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