Planning new house, gable ends. Zone 5. Decra steel roof over 5/8" CDX plywood. It will have 36" gable end overhangs, to make best use of 4' x 8' plywood sheathing + 13 decra panels wide. I plan to build strong support for this overhang, by tying 2x6 12"O.C. outlookers (barge rafters) back into the inboard 16" TJI rafters, sitting them on top of the dropped gable wall. This will greatly interfere with venting & insulating the 1st gable end rafter bay. My question is: can I use CCSPF in these end rafter bays & vent the rest of the house?