I paid an HVAC engineer to design a mini split system for our a-frame. For the open great room, he stated I should have a mini split that blows upwards toward the quite high ceiling to the tune of 4 tons. There are a few units that I can size that blow up that large, but I am concerned about the noise? Does larger get louder? Also, the SEER on one of these huge units is only 15-16. If I go smaller I need to put another one over in the dining room. Since the other 4 units are multi zone, I had wanted a single zone redundancy for the living room unit.

Should I downsize the living room and make it a 2 zone multi-zone system (and reduce the efficiency) , or downsize and make it a 5 zone mulit zone and 1 single rather large single zone in the living room?  Also, does it really need to blow up toward the ceiling as HVAC engineer directed?  If I go with a more DIY option, I can only get wall units that blow down, but wow oh wow at a much cheaper price.