When I got my first hive (a WBC) in 1959 it was custom and practise with these hives to have loads of sacking etc on top of the quilt ( crownboards were not commonly used in my part of the world back then except for clearing with porter escapes ) and many people packed the gap between the inner boxes and the outer lifts with all sorts of stuff including straw, old blankets etc. Swapped over to Nationals in 1972 and have always covered the feeder holes apart from when feeding. I have never ever used matchsticks for ventilation although do admit to using one (sometimes two) still to light my smoker or to suspend introduction cages (if I don't have toothpicks to hand) I have known hundreds of beekeepers (including Ted Hooper, Eva Crane, Cecil Tonsley and Geof Hopkinson) over the years and only ever come across a few that actually propped up crownboards with matchsticks for ventilation . I have been using 50mm squares of Celotex etc under the roof for insulation for about 20 yrs and find colonies use about 3 Kg less sugar over winter and wintering 25 to 30 colonies that saves me about £45 a year on current prices. Surprisingly apart from using less stores I have not noticed (and I keep good records) any obvious difference in colony losses or in honey production from using the insulation layer.