Zanna, What would you be hoping to gain by the breeding? If you are trying to double up genes that is one way to do it... It may also tell you what they hold by doubling them. I see no reason to breed forward using a full brother. I would like to know why you would want to.
As long as you are keeping record of the crosses and you have the room, it is fun to find out what each bird brings to the table genetically. I have a pen full of "mistakes"... They aren't really mistakes.... just learning curves. In order to find out what my males have I kept a few birds that I knew carried genetics for wheaton, birchen, and partridge/wild type. I could use the birds to help me find a suitable male... It takes me about 2 years to know whether a male is good for breeding forward... I have to wait for the hens to grow and for the egg color as well.... I have a couple new prospects this year. Have been growing them up since I lost my main squeeze. Sad to say they don't measure up to what I had before but I couldn't use the male offsprings back on their mothers because of doubling up some of the genes...