So I have been taking the 1/2lb or 1lb fresh frozen, putting in the blender with ~8cups of warm to hot water and blending for 1-2 minutes. Pour out through a strainer bag and put it back in the blender for a second wash with another 8 cups. I started with just 1/2lb but I found it a bit weak for my liking. 1lb was a closer to my regular dry medium grind strength on a typical night.
I would not use an aluball. The aluball shaking action works reasonably well with medium grind as it mechanically washes the kava and you get a good result (but not quite as strong as kneading). If you don't have a good blender I would just go with a good strainer and knead it like a typical medium grind.