I have a Webasto AirTop with two outlets in the master cabin.
Where did you find space for the ducting into the salon?
There are what seems like factory installed outlets in the main saloon just behind the kitchen above the settee - a big wooden vent, and in forward bunk on the bulkhead to the toilet, but there is no surviving ducting and I can't figure out where it went to and absolutely not how to connect anything to the master cabin.
I have a 410 and since they're similar, this is what I think.
I also have the heater in the aft lazzeret, 2 outlets in the master berth cabin. Sure, the forward cabin and head get the least of the heat but they eventually are warmer.
The outlets we have in the main cabin are completly separate as the boats would have seperate 2 a/c 's.
I had no way/path to get ducting to the main cabin and I think it would almost be way easier to just add a second unit to the forward area.
Just my thoughts and experience, others may have better ideas.