John its only common sense that you dont need to be on the dark as your young birds will be on natural darkness, Spence & Nichols, and Ronnie Bigwood done this for years, however it doesnt mean it will win you a national, there are many ways to keep your birds with a complete wing, darkness, light and as you stated pairing before december the 10th. However many people swear by now having young hatching xmas day and a tub of vaseline in the loft to slip there rings