I would like to insulate my 2 car garage. I use the the ceiling to store wood so I want to leave the ceiling open. I would like to insulate between the top cord of the roof. The trusses are only made with a 2X4 so I don't have much depth. The roof is asphalt shingles and I don't have a ridge vent just soffit vents. I'm in Denver, Colorado so the temps can range from 0-100 degrees. I've been researching radiant or reflective insulation and solid foam insulation panels. What would be the best, easiest way to do this for a DIY. I know I won't get much of an R factor but think anything would help during the winters. Thank you.