ive used both the nylon brush on a drill and a wire brush on my drill, if you are gentle the wire brush works great, Of course it will have microscopic scratches on the deck but nothing to be worried about. Ive done this every single time and never ever had a problem with headgasket failure because of it.
Now that is technically not the proper way to do it. If you want to do it perfect take the head and block to the machine shop. The nylon works great as well but i dont usually have that on hand. The nylon takes a bit longer to get the material off but it does come out a bit smoother.
i would not hesitate at all to use the nylon or wire brush on a drill. Again ive done too many to count on all different types of vehicles and never had one fail.