This is just some of my personal thoughts,
I like an early starter, first look at a pig at 4 months, trained untill a year old, and by then they better be freaking out to get to a pig. If not, cull.
With the broad range of genetics you have, breed them real tight at first, selecting for conformation and performance, keeping the whole litter untill they are a year old (that's the only way you know what you've got, look for consistency through the litter in all things) keep the best Male and female from each pairing at 18 months, cull the rest.
I always want to breed back up the line when I can, sire to daughter or grand sire to grand daughter. I like that better than a litter mate pairing.
Once you get pretty close to what you want, out cross every third cross, that way you can breed real tight twice then out cross, and repeat. If your blood is good and you have selected you could be close to what you want in 6-7 generations.
Don't settle for less than what you feel is perfect. I am line breeding two different lines right now and its a lot of work and a lot of dog food, but well worth the time.
here is good read
http://www.westwindgsps.com/linebreeding.htmFor me personally line breeding is done to set the traits you want so that your outcrosses will be very consistent and have the hybrid vigor we all want. So to me line breeding is not an end unto its self, but a way to produce out cross dogs as the final goal.
