its a lil hard to explain but i cut the hole slightly smaller and bent the lip in right round so that they sit into the guard nice n flush n dont fall thru, when i cut the hole out i left tabs which i bent in so that they line up with the original lugs on the back of the flutes, i replaced those lugs/ clips with bolts and locknuts so i could just push the flute into place get my hand up inside the guard n put the nuts on, hope u can understand all that lol