Hello,
New construction in Zone 5. Our plans called for a unfinished attic and I had attic space built into my roof truss system. As an afterthought, my wife and I thought it made sense to insulate our attic space in case the family grows and we need some extra space. (No HVAC system is in the attic, when one is added later it would be within the conditioned space)

The only problem is that a majority of my trusses are only 2x6s and 2x4s. (There are fewer 2x10s) Do you have any advice for someone in our situation?
I outlined what I feel are my options below:

Option 1: 5.5 Inches of Close Cell against roofline (very, very expensive)
Option 2: Cut a ridge vent (don’t have one right now), add soffit vents and insulate around the attic floor and kneewalls.
Option 3: Cut a ridge vent, add soffit vents, baffle and insulation up the roofline (would require extending plenty of rafters)
Option 2b/3b: Skip Ridge, go with Soffit & Gable Vents???
Option 4: 3 inches of Close Cell (to hit R20 Code) + Batts for Flash and Batt system  (would require extending plenty of rafters)

Thank you