I have continuous air soffit board running the entire length of my roof. The problem is when I’m up in my attic, it appears a lot of the blown in insulation and insulation bats coming up through the walls have blocked airflow into my attic. I can only see light coming through about 20% of the rafters, which probably means a lot of the ventilation has been blocked. I have a very cramped and complex attic, which would make it very difficult to clear all the insulation to get unrestricted airflow. How important is it to have outside air at the bottom of my rafters?
Without the benefit of viewing your attic, I would guess that you have enough ventilation to satisfy the conditions. Just make sure that the radiant barrier does not cover the vents at the ridge or even at the eaves. Leave about 6″ on both sides of the roof. If you have areas of the attic that cannot accept a radiant barrier on the roof line, put it on the floor on top of the existing mass insulation. Be sure the material is perforated.