Mini-splits have no ductwork. You have an individual head unit in each space that you want to cool and awired and coolant lines that come though the outside walls, attic, etc. The only choice you really have to make is type of headunit, wall or ceiling "cassette" Mini-splits might have been a bit late coming to the US. The first place that I saw them was in Cancun. The house in question was basicay a three level concrete bunks with slab celings/floors. Hard enoug to run wires for lighting much less ductwrok So, mini split wall mounted head units with a couple of like 1 inch holes in the outer wall and the heat pump(s) up on stands outside.