That's quite a lot of excellent points you raise. When I first grew acacias I babied them way to much and they died and so I adjusted but reading your post I can see that I've swung too far in the opposite direction. I have been gentle with watering them, unfortunately when I got to our new place I put them in a place that got a lot of heavy watering due to a malfunctioning gutter and so that knocked a lot of cotyledons off. I'll have a think of where is a good place, probably where I have my caapi cuttings going.