I have two AC zones in my house one for the west wing and one for the east
wing. The west wing is a 4 ton cooling the living room, dinning room,
kitchen, laundry room, utility room, pantry, one bath and a hallway. The
east side is a 3.5 ton cooling 4 bedrooms, 3 baths and a long hallway. In
the middle connecting the east and west wing is a family room which is about
32'x16' with the ceiling varying from 9' to 16' tall. This room has a
fireplace and lots of glass doors and windows that leads to the pool and
it's never cool enough and it's at the end of the AC supply for the east
wing.

So I am thinking of capping off the supply for the family room and let the
other rooms get cooler and install a split ductless unit (like a Mitsubishi
Mr. Slim Series MXZ-2A20NA for example). I have calculated I need 20,000
BTU. I don't think I will need a heat pump since I am in Miami and I do
have a fireplace in that room if I ever need it.

Questions a

(1) What are other brands I should consider?
(2) These unit needs an outside condenser too do they need to be floor
mounted on a concrete pad or they need to be wall mounted?
(3) Where should I place this unit on the inside? I assume it has to be
placed in the middle and as high as possible) but I have a tied beam and a
row of windows and glass door and the only spot is the corner, but I am
concerned putting it in the corner will cause uneven distribution of the
cooling, the AC guy who quoted me says it does not matter air will flow
evenly...really? Seems illogical to me if the room is 32' long it will not
cool evenly if it's mounted on one side right?

Thanks,

MC