Hello, and thanks for all the HVAC education so far! I’m choosing minisplits for 2 buildings in Zone 2A:
1) Communal kitchen/living: 721 sq ft / 8921 cu ft, used by 6-7 people. Attached Manual J+S (from a GBA-recommended consultant) specs a 2-ton unit.
2) Bed/bath ADU: 401 sq ft / 4173 cu ft, shared by 2 adults and 3 kids. Report specs a 1-ton unit. Questions:

1) Does the report look aggressive enough? The guy said he typically recommends 1 ton/1kSF, but our buildings have vaulted ceilings, many windows*, and high internal gains due to many people sharing a small space. He also said: “I see you spec’d an indoor summer temp of 78F, but I designed at 75 for the software, to make sure there’s a large enough Delta-T to produce an accurate report. If I input 78, your living room drops to a 1.5-ton on the edge of a 2-ton.” *(RE: green-ness: we’ll house 5+ people in ~1100 SF… the design’s openness makes it tolerable!)

2) What’s the risk of just going with the 2-ton in the living room? It’s only ~$300 more than the equivalent 1.5-ton. GBA/Dana: “Up to a point [~1.5x], oversizing is GOOD for efficiency! Mini-splits are modulating systems, and typically have much higher efficiency at part load/lowest speed.” Still, Manual J already oversizes, and I don’t want to lose dehumidifying capacity right?

3) What’s the *best* model for my load? The report recommends the Mitsubishi MUZ-GL12NA (/24NA). How can I best compare it to same-sized Fujitsu, Daikin, etc.? Fujitsu excels in SEER, Mitsubishi in turndown ratios, and Daikin makes the only minisplit (Quaternity) that has its own humidistat… it’s pricier, but might it save me the hassle of dealing with a standalone dehumidifier? I can’t seem to find info on its capacity when used that way. Its other specs aren’t amazing. But it’s often muggy and 72 here, so we’ll likely need dehumidifying on non-cooling days…

4) The guy said that if we use exterior solar shades on ~half the windows, we could downsize to 1.5-ton. But good manual ones will run me ~$2500, and won’t last forever in TX sun. How can I compare the electricity costs of a 1.5-ton vs. a 2-ton unit? And should I consider shades as a matter of comfort either way? Sun streaming in can make for uncomfortable hot spots in my current leaky, single-pane window’d house w/AC… but will that be an issue with the 0.21-SHGC, low-e windows I’ll have here? Thank you!