Hi Luke
I have had an idea, as we have seen in your challange games different players make different lists. And since your brother´s guard list is very strong, both well made and well played. It would be fun to se how he would counter a guard list that you have made, with different armies that you have. And what kind of lists he wold make with them. Maybe you have done this privately already, but it would be a leraning experiance on different armies and how to counter them. I mostly play with my friends and we have tried this, it made for some interesting lists and games. You could call it "Sting the bear" or "Bearstrike".
But again, just an idea but I hope you will try it out, your take on a guard list would be fun to see.
Keep up the good work.