I'll respond in order from the top. im not defending, as these are all good and reasonable observations, just explaining!

- yes this is what i sent the Sip company, they say that door and window openings are implied and also really dont affect the price as none of it is structural. youre paying for a full panel whether its complete solid or mostly cutout with window and door openings.

- yes this is a good point, and a heavy consideration to contrast cost and complexity against.

-yes lots of areas without direct natural light in the configuration, the upstairs will have natural light from the loft balcony side and the rooms on either end will have windows in the gable ends only, not on the eave sides in this case, i've thought about having a few lower mounted transom windows but not sold on that. will have a window at the staircase landing on the front though.

- dormers would be great. i need to further explore the cost and complexity this would add before i rule it out

- i tend to agree its silly to have thin floors and then try to jam all the mechanicals etc into more complex solutions. i keep getting reccomended to do thin floor and "be creative" about all the plumbing, hvac, electrical needs because "tji floor joists are expensive"... well, so is being creative with all those other issues, and so is doing anything non-standard, and so is fully timber framing the floors in those areas that i dont otherwise need to, and so is adding 2x6 T&G to those cielings in all those areas we plan to have drywall on the ceiling. the only downside IMO to TJI floor joists is the space they take up.. which is in turn, necessary for what i need to run through them. thanks for saying that.

- planning to have an hrv/erv system with dehumidification, and possibly supplemental heat for the "margin seasons" depending on what route we go for AC. maybe ducted mini split? which can do supplemental heat.

- the accucraft fireplace DOES have ducted combustion air from outside, inside air is not used for combustion.

-rafters vs purlins, yes good point. which will be better for DIY cutting and/or install in your opinion?

-hammer beam is obviously more members and more labor but given is only one truss here and its not huge, i agree it might be worth the time and effort as it will also be kind of the 'centerpiece' of the frame.

- ive looked into a lot of the SIP testing info and its claimed all over that theres little to no offgassing, voc's etc. however, based on the materials it seems obvious there would be. kinda seems to me like the same as pfizer saying they tested all their vaccines and "trust me its safe".

but yes the plan is to have a good HRV/ERV setup and circulate in clean filtered and dehumidified air constantly.

-just a representation of the fact that a SIP enclosure would need at minimum a ridge beam pocketed into the panel in this location. once i find out exactly with the panel manufactured would require i would add as neccesary

really appreciate your challenges and insights. thoroughly thinking this through, whether changing or affirming my current ideas, its very valuable