HELP!!! Bantam+normal size=????

I have game fowl and I recently got a bantam Phoenix however he is not that small, I'd say he is between bantam and a normal. I wanted to know what would be the size of the offspring, as well as wether the offspring will carry the phoenix long tail trait because the two hens he has are not phoenix just regular game hens. Should I keep the eggs because I know they are fertile, but I don't know what the offspring will look like.