Using only 1 1.5" intake on the Dart will cause a LOT of restriction on the intake. There is a reason why Sequence has a 2" intake. The Dart is a high flow-low head pump so it can't be restricted. As soon as you start restricting portions of it, that'll dramatically decrease your flow/output. I would look into 2 1.5" intakes.
As far as outputs go, if your going to go with 1", then you need at least 4 1" outputs or else you will be restricting it. You could get away with 2 1.5" outputs too, that way your maximizing flow and minimizing the restrictions as best as possible.