I use a national size wood-framed clear polycarbonate crown board on a Pain's poly hive, with the poly roof on top. The poly roof does not fit snug as it does if directly on the hive, but stays on tight with the strap.
Tidying things up for winter and doing my last inspection for awhile. Finally saw my queen that I have not seen for nearly 8 weeks and was pleased to see that she had begun laying again after 4 weeks off-lay. I did not treat her hive for mites this season so she went off-lay for some other reason.