Question-and-Answer Resource for the Building Energy Modeling Community
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I suggest option 2 - make a custom material.
You'll have your wall construction as you normally would, but take your studs + cavity insulation and make it one material that matches the thickness and de-rated U-value. This is what California Title 24 does for compliance models.
There is an excellent discussion here https://unmethours.com/question/26920/title-24-vs-901-u-factors-for-metal-frame-walls on de-rating wall insulation. I recommend referencing Title 24 stated values, which are from THERM models that account for thermal bridging.
