I break down plywood sheets outside of my shop because my shop is small. I can cut the pieces very accurately with the following method. It's so accurate that I don't need to even trim them to size on the table saw, unless I'm making something where the pieces need to be cut to within a few thousandths of an inch accuracy.
I have a 30 X 70" table that is just a 1 X 4 rectangular frame with 2 X 4 cross pieces laid flat and flush with the upper edge of the 1 X 4 frame. These 2 X 4 pieces are placed only where the legs and leg braces need to attach plus one across the center of the table, for a total of 5. The 2 X 4's and 1 X 4's are all joined together with biscuits and glue. There is no solid top on this table. It's just a frame. The only metal in the whole table is the conference table leg assemblies and the 1/2" long screws that attach them. There is no metal anywhere in the top 3/4" of the table frame, so no chance of hitting metal with the saw blade.
I use this table much like a pair of saw horses, setting my saw blade depth to cut the thickness of the plywood sheet that I'm breaking down, plus 1/8 to 1/4". I don't worry about making the saw kerfs in the top surface of the table. If It ever appears to be weak from too many shallow cuts I can always make a replacement and transfer the legs to it, but it's going on 14 years now and the table isn't anywhere near ready to replace. The beauty of using this table is that when you make a cut, the pieces remain on the table. Gravity keeps them there. Nothing falls to the ground or the floor and the off cut don't break from the main piece as you reach the end of the cut either. Every cut is clean all the way to the end. When the work is complete, the table legs fold up into the 1 X 4 frame of the table and it stores on edge, leaning against my sheets of plywood at the end of my shop. I bought the banquet table legs from Woodworker Supply. Woodworker.com: EBCO HEAVY DUTY BANQUET TABLE LEGS
For splinter free cuts I made a 1/4" thick base to attach to the shoe of my circular saw. I attach it to the saw base with two 8-32 flat head bolts and nuts, countersinking the bolt heads in the base, one through the front and one through the back of the saw base. Once attached, I plunge cut the blade down through this base, then mark the area where the blade guard needs to go through this base to operate safely, but it's important not to remove the area around the leading edge of the blade. This area will function as a zero clearance insert to prevent the blade teeth from chipping the wood as the teeth rise up through the wood being cut. Now remove this base and cut away the material that prevents the blade guard from operating. Re-attach this base to your saw and it is ready to cut splinter free panels. I use a thin kerf high tooth count (60) carbide combination blade for breaking down plywood.
I have two aluminum Pro Grip wide body straight edge clamps, a 50" and a 105" long, that I bought from Peach Tree Woodworking PRO-Grip Straight Edge Clamps
(located about 1/3 of the way down the page). These straight edges work very well and clamp easily to the sheets.
I eventually want to make a thicker saw base with dados in it so that it will allow the saw to ride on top of these extruded straight edge clamps, like a track saw but cheaper, but I haven't done this yet.
If anybody wants pictures of all of this, I'll take them and post them.