I make most of my hives and supers, i leave a 3/8 space above the top bars in all of my brood and super boxes. I have several bought brood and super boxes that the top bars are even across the top of the boxes, but have 3/8 space on the bottom of the boxes and when i mix the two i get a 6/8 space and that means burr comb, but i would rather deal with burr comb than mash and kill bees. I make a migratory lid with a 3/8 shim under it so when i come across a super with know 3/8 space on top, i can give it a 3/8 space. I don't have many of the no space on top of the boxes now, trying to keep extra equipment when going to outyards is a pain, you more than likely won't have with you what you need! Hope i didn't confuse any of you. Jack
PS, the boxes i make are even across the bottom of the box and frames, this way i don't need a inner cover.