Edit: obligatory disclaimer that I am no where near an expert in crafting.
Ingenuity I is the same as II when you are doing touches. Ingenuity II is superior on synthesis.
Factor in the difference in CP and the # of touches it takes you to complete a synth and you'll be able to choose which one to use.
For example, if you're in a fresh level 50 crafter and ingenuity II doesn't one-shot with careful synthesis, then you could be using ingenuity I instead for your byregots>CSII>CSII.
But once you're max everything, you may not even have the space to equip ingenuity I let alone find time to use it
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