I just finished installing A/C in my friend’s 380 (I already have it) and this is what I did:
Webasto 16k unit is mounted under the settee just fwd of the galley sink. This is about the only place a 12k or higher unit will fit. I used the existing thru-hull for the icebox pumpout as the intake, teed off the line just above the thru-hull and prior to the anti-siphon U mounted up behind the stove. The line off the tee goes under the galley floor transversely toward the bilge that is hidden under the screwed-down galley flooring. It then follows the bilge pump line fwd into the smaller accessible bilge adjacent to the settee. In that space I installed the water strainer so that if it ever needs to be opened/cleaned the water just spills into the bilge.
After the strainer it goes up through the liner floor