Whoops!

Found my first real flaw in my plan today.

I engaged DH to help me put the wool onto the particle board. We wrapped it, stapled it, covered it in muslin, and then put it on top of the cabinet
Don't know if you can tell, but the big gap in the middle is where the top no longer fits onto the bottom. The wool (army blanket, doubled over) adds 1/2" of height, which means that my wonderful dado-like objects no longer work.

So, here was the solution:

While the original staples were still on, I carefully went through and stapled into the edge of the board instead of the bottom. (The pic above shows the top turned over) Then, I removed the original staples (fun!) and cut off the extra padding, so the board fits on top just fine. I hope I put in enough staples to make it stable.

If I were doing this over, I would just put a simple 1/4" or 1/2" top on the cabinet and make the pressing board separate to sit on top.