We usually use a fluorocarbon tippet as it is clear and slowly sinks but does not usually pull the fly under. It leads to a neat presentation. Always change the shuttlecock fly after a catch as the cdc fibres will have clogged together. Let the shuttlecock fly dry naturally in your waistcoat fly patch. Never grease the fly as the cdc gives loads of buoyancy and floatant will clog the cdc and the fly does not fish properly.