I have a 1950s ranch with a hip roof that I am adding roll insulation over the blown insulation. The rolls are running across the joists. With the hip roof design the roof joists run close to the floor joists for about 30" to the eves. I know I have to keep an air space up from the eves but how far back do I put the rolls? I put a roll back until it started to touch the roof joists with plenty of air space but its still about 30" away from the wall below. If I install baffles, I could push the insulation back further but the r30 insulation would be crushed against the roof joists.