The dampening process is a bit involved as it is passive.
I dampened a set of blotters much like I do the Rives BFK. Then I place 2-3 pieces of Japanese paper between the blotters.
So here is how it goes. Say I want 40 pieces of Japanese paper dampened.
I will need 21 sheets of dampened blotters. So I soak 11 blotters for a short time- 5 minutes or so (unlike the Rives, blotters soak up quickly). I build a stack with dry and dampened blotters: dry blotter, dampened blotter, dry blotter and so on finishing with damp blotter on top. I have this stack on a board and place board on top (I have been using masonite with mylar on one side to protect from moisture), wrap up in a large plastic bag and place a weight on top.
I allow this to do it's thing for 24 hours or so, flipping the stack half way through (I usually flip the stack just before bed).
Then in the morning I take the dampened blotters and build a stack by starting with damp blotter, 2 dry sheets of Japanese paper, damp blotter, 2 Japanese and so forth finishing with damp blotter.
Then I follow the same procedure, wrapping in plastic bag, under weight, flipping half way thru for around 24 hours. Depending on the weight of the Japanese paper you may be able to do 3 sheets per blotter sandwich. This is very involved, but is a consistent, passive way of getting evenly dampened paper.