For note, there’s no “proper” synthdef other than supercollider synthdefs. Overtone is just another approach for creating supercollider synthdefs. There’s no extra magic. The only thing to be aware of is that sonic Pi needs specifically named synth args (as documented in the tutorial). The slide args are explicitly added in to all sonic Pi synths as part of their design - so if you don’t add them yourself they won’t be there 
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