Roma, im deeply impressed with your knowledge.
Yes, there Is a problem with metal condensating and It does need to be addressed.
Do not install SS over bare decking with just synthetic underlayment. heck no!!!!
None of them are a good water barrier!!!
There are several ways to address the problem.
1. Use ice and water shield underlayment.
2. Use ice and water shield along with batton strips.
3 install quality felt directly over shingle roof and install.
4. Install insulation board over shingles and install.
If you choose shingles, choose the Malarky!!
Stay away from owens cornings Duration series at all cost even if they are free.
Owens corning does make the very best ridge vent.
Owens corning " sure vent"
Most bold, robust, strongest attractive looking vent
Actually improves the look of the home.
Dont use that ridgevent in a roll trash.
It looks horrible.
Roofers use it because it installs really fast with their nail guns.
Yes, only cut the holes in ridge where there is attic space.
but DO go all the way end to end with the vents for cosmetic purposes. To make your house look great!
Also make sure the ridge vent hole is not cut too wide!!! I make sure mine is no wider than 2 to 2 1/2 inches wide total.
Many roofers have been cutting 2 inches off each side of the ridge due to manufactuer instructions and they have lots of trouble..