i probably would as well,it would be as close as possible to what you originally wanted to do,but just because 2 dogs are off the same breeding dosent mean they are of the same bloodline-i.e they could throw very different pups.
Even tho the two dogs in question are litter brother's, and the bloodline has been kept as close as possible over many generations. Sure the pups being thrown would not being that different?
I am no expert and correct me if i am wrong!