I have a two part question:  I’m designing a home with a standing seam metal roof which is continuous over two different structural systems.  Section 1 in the attached image will be stick framed with 2x12s and will have a vaulted ceiling. Section 2 is framed with trusses, and will have a ceiling attached to the bottom chord. I am presuming a warm roof for section 1.   This is in New England: climate zone 5. 

Question 1: Section 2 can have a cold/vented roof, but should it? I’m worried about the transition between the two strategies. 

Question 2: Similarly, I’m uncertain as to how to transition between an un-vented/warm roof and a deep cantilevered eave.  How does one protect against ice dams in this scenario? 

Thanks for any input!