I tried one 6 inch hole with oil pan under the hole , 2 six inch holes with oil pan under, the back half screened with oil pan, neither of these worked as well as full screened. I only tried one hive of each but it only took one full screen to completely convince me. I caught 23 SHB the first 24 hours of full screen, nuff said. With a quilt top and DSBB i see no bearding in hot weather here in NE Texas, no mold, or condensation in cold weather.