You don't really need to do anything to the inner cover, as the telescoping roof covers it. However, mine were sitting in a stack as I put the Tung Oil on, so they did get a coating on the outside edges. I didn't put any on the large flat surface. Would I do it again, when my complete Flow hive arrives? Probably yes, because I like to be consistent!
Love your photo - hive in the Fire Station! Nice looking job on the hive.
It was fun meeting you at the Beekeeping Society, David enjoyed it too.