Before I got my track saw (Triton), I used an aluminum L extrusion and my 18v DeWalt circ saw to break down ply. I had to get a decent blade, but the offset to the blade was exactly 1 1/8th, so it was really easy to mark the cut. Simple clamps held it solid. Now, I really like the track saw because the edge you cut off is the edge of the cut. And I replaced the blade with a higher quality one so tearout just doesn't happen with BB ply. Cheap China ply is a different story. I tape the cut line on that crap and still get tearout. Discovered on one sheet that the middle layer was small strands of banboo and splintered no matter how carefully you cut.
The more I do, the less I accomplish.