CS, I made a 1/8" acrylic coverplate for my skimmer to cut down on saltcreep. I bought a 3" hole saw to cut the hole so the insump skimmer would fit through it. I used the cutoff hole and filed it down to slide into the skimmer body. I then layed out and drilled 3/32" holes to make my diffuser. I adjusted the diffuser up and down until I got the best and tinest bubbles. The skimmer really works nicely and makes lots of skimmate.
I bought a 3/8"x1/2" PVC
elbow and channeled the venturi airflow down below the diffuser plate with another elbow to channel the air upward through the diffuser and adjusted the amount of air with a top grade airvalve. The way my skimmer hooks up is a real bear, so I won't take it out to get some photos until it's time to really give it a good cleaning. I will try to draw you a diagram of it.