I don't have pics of the circular saw attachment, but it is essentially the same as what I did here with a sabre saw.

In the pictures you can see how the box of strips is arranged around the base of the saw. With the circular saw I did not add legs, but I did screw on a long fence.

Once the saw was mounted to the plywood, I did a plunge cut to expose the blade on the bottom of the plywood. Then, after unplugging the saw, I used a scrap strip as a spacer and placed a straight board 1/4 inch from the exposed blade. This was attached to the plywood with two or three screws, and I did a test cut.

What I got was a little bit thicker than I wanted, but close enough that I can plane the strips to a more consistent size later--so i didn't bother changing anything. If I didn't have a planer I'd have used a pencil to draw a line on the inside edge of the fence, removed the screws holding the fence to the plywood, moved the fence to just barely cover the pencil line, and secured it again with screws in new holes. Then another test cut.

If I wanted to get fancier I might have used a wider board for the fence and cut slots in it, then used bolts running in those slots to give me some ability to make adjustments. I decided against that route as i wanted to have a jig I could return to time after time without tinkering with the adjsutments each time. With the frame of strips on the one side of the plywood to ensure the saw is reseated int he same place each time, and the fence screwed to the other side of the plywood, I can pop the circular saw on and off so it can be used for other things.

There are some safety concerns with jigs like this. The automatic blade guard on the circulr saw is blocked by the plywood, so the blade is always exposed. The large size of the auxilliary base makes it difficult to reach around it, so it is unlikely that you would cut your fingers, but you could damage the blade or cut some other part of your body if you are not careful.

Hope you get the gist of the idea from these pics of the sabresaw.

PGJ