I was just reading this for the first time. Looks interesting.
I have that same shop vac, and had a question about the filter. Mine came with two filters. One for dry, and one for wet. Are you saying to use no filter at all when your extracting the water?
Also, you said that you just scoop the water out of the bucket onto the floor with your hand. Do you do the same for the seats, or do you spray it on with something?
Thanks for the great write up.