Your drawings look great - you're fortunate to have that amount of space to use!
I wrote about how I decided on my HVAC spec on my blog but broadly speaking, there are two types of HVAC systems you can choose from. The first type is a ducted, forced-air system that circulates via a heat exchanger and can include a dehumidifier unit. The total volume of air in the system is cycled 6-8 times an hour and is ‘topped up’ with 30% fresh air. The boiler will need to be housed in a separate room, the ducting will need to be large and the silencers even larger!Do you have any info on what is best, mini splits or central A/C.
The second type is a ‘ductless’ mini – split system. This is where air circulation and heating / cooling are separate and only need to move 30% volume of air compared to a forced air system (the fresh air you need to breath). This type of HVAC is less efficient and will need a drain pipe to be installed from the AC condenser unit through the inner & outer leaves to the outside, but has the significant advantage of being cheaper to install and requiring smaller silencers.
Looking forward to seeing your design progessing. Best wishes, John.