Mark,
8 cocks 5 hens sounds like pims a clock to me also seems like its an indeal sitatuon and wish i was in your seat. Personally I would only be racing the 8 cocks, paired to 4 hens. 2 cocks to one hen, think of the jealousy you can create. It does help to get birds in a strict routine but there are many timed chicken feeders on the market that will help you on your task. However your cocks ideally would should be let out twice per day, but it isnt the be all and end all, one of my best years was when the cocks were only let out once per day but they flew with plenty of vigour and vitality. There are many road that lead to rome, with natural birds they need to be trained, widowhood flyers do not train after the first race, they do all there training around the home.theres also no need for the annoying stage of stopping your hens from going eggy for a race ect. widowhood is ideal situation for the working man, if ya can do it. read up on it as much as you can an im sure you'll be able to work your way round it. Best of luck
Ryan