[jyl]

Looks like there are some ceiling cassettes for 16" centers. Hmm. The way the joists run, I could bring the lines up inside the exterior wall (that the outdoor units are on) and through the top plate, then between joists to rooms 1 and 2 (the ones nearest the outdoor units), then over interior wall and between more joists to rooms 3 and 4 (the ones on the opposite of the building from the outdoor units). I would have only two 90 deg bends. I think I'd buy rolls of bare copper tubing, then apply insulation after the lines are in place and tested. I learned at my house that you can't really "pull" pre-insulated linesets.

OTOH, with wall units I could simply bring lines up inside the exterior wall for rooms 1 and 2, and also between joists of rooms 1 and 2 to get to rooms 3 and 4. Rooms 1 and 2 are already gutted with ceillings and walls off, rooms 3 and 4 are intact and I wouldn't need to cut their ceilings up. Still need 90 bends. And of course in future, it would be easy to replace the indoor and outdoor units and use the same lines.

Hmmmmmmmmm