Think you might come out better focusing on his proven abilities that you favor rather than attempting to play the % of pure blood game. You already know he has a touch of multiple breeds in him which is no problem but no matter how you cross him your not gonna come up with anything more than a math equation on top of having limited info about his heritage.
Rather than that focus on finding a good gyp of any breed that you prefer that shows favorable proven abilities that will reproduce or add to the traits that you wish to keep.
I have been told to not attempt a cross until I look at a dog and say to myself "man I wish I had ten more just like him or her" good solid advice.
Sounds like you are confident about your male so just find a similar talented female and find out.
Hope you get twelve more even better. And hope the advice helps. Good luck bud.
I guess this is just a long drawn out planing process... And im just getting started!!!
but I want to do it right is why I ask, so thanks for your input. Fred is a really good dog, but I can't take credit for him. Jimmy did a great job with him, and with what Fred already had in his blood he turned out great. Fred x Soka should definately happen...