I think it took me about three months to get the settings right; but I still fiddle around with them from time to time – it’s a way of passing the long winter evenings.
I think getting the basals sorted overnight is fairly easy – you don’t really do much, aside from sleep, so it’s all nice and stable. Working out basals during the day I found a bit more complicated. Some times I ended up throwing the damned pump across the room with frustration (just as well it was attached to me). But it’s worth the effort!