I realize that you're trying to recycle the remains of your table saw, but it sounds as if you need a router table also. I was given an OLD well made double pedestal desk a couple of years ago with a good flat top. I removed the legs and put it on a frame with casters, removed the center drawer, and cut a hole in the center of the top to mount the router. The drawers in the pedestals are handy to store bits, etc. When I built the frame for it I made the height the same as my tablesaw so I can lower the router and use it as an out/infeed table as required. This might be more functional and easier to do than having a hole milled in the tablesaw top.