I couldn't bother with Dry Weight, SG and all the calcalution. I just did the quick and dirty. Assuming dry weight is 80% of wet clay weight, then add 5% stain. Will see if this dirty trick works.
I am a copy-cat this week, copying from this video on my rounds on Youtube. I didn't follow it to the T. I did it sort of off the top of my head and it looks great to me.
Check out what others are doing at Mud Colony.