Sweet spot and erg mode

What is the best mode to be in to get the most benefit from these sweet spot plans? In the descriptions they seem to be suggesting standard/resistance mode rather than erg mode.

Where are you seeing that?

For sweet spot workouts it’s personal preference really. Some people will say that long efforts are easier in Erg, some say that managing your own gearing/effort forces you to concentrate. Try both and see which you prefer.