Guys, I apologise for any confusion.
The ceiling from standing inside the room has a center, horizontal section that is 9' wide which meets roughly 45 degree sides going down at an angle for 64" inches to meet the verticle walls that then run 47" inches down to the floor.The horizontal ceiling section and the full house length crawl spaces behind the 47 inch verticle walls I'll insulate with fiberglass batts.
* Its the ceiling sections that are at the 45 degree angle that I'm unsure what kind of air flow is needed, if any for heat and moisture to move, so I really need your help.
I don't see any alternative for insulating these angled ceiling/roof sections, and still leave room for air/heat/moisture movement.
After reading about vapor barriers and mold, I'm going to have to think about that.
I don't want to cause a situation that causes mildew and mold by putting these panels between the rafters. Foam panels have a somewhat porous nature.
Oh yes, I live in northeast Ohio, as far as heat/ moisture levels are concerned.
neal - you're right of course. I just figure that some insulation in those ceiling sections has to be better than none.
Bridgeman - yes, they are indeed rafters, on 24 inch centers.
joecaption - I apologise for the misleading description, I won't be insulating all the way to the top of the rafters, as I've just described above. But thank-you for your information about how to do that.
It looks like the third floor was finished at original construction of the home in 1923, and has never had any roof vents until I had some installed a few years ago with new shingles; which leads to a different question for a different thread.