I think you also have to be near enough to the NPC for the timer to wind down before another skill can be taught.[/quote]
Aye, they need to be in the reality bubble to really have any effect… But when you got a nice base you can take them there, order them to not touch your shit, have them teach you/batch create, and then tell them ‘youre leaving’ for a while (not stand guard), that will make them ordinary NPC’s who don’t need food/sleep.