All the ideas I have seen here are great. I happened to do mine a little differently. I planed some oak to the proper thickness and then roughed out blanks about a half-inch larger than my stock insert plate. I then used double sided tape to fix the wood to the stock insert and then went around it with my router using a pattern cutting bit with the ball bearing riding on the stock insert. It's exactly the right size and you can do it with your eyes closed (although this isn't recommended by OSHA). While you're set up, make a few of them for future use. I even made one that is just for 45 degree angle cuts because if you tilt the blade on the your new insert it will no longer be zero clearance. The last thing I did is to drill a 3/4" hole at the far end so I can get my finger in to pop it out. They fit so snugly that this reduces some swearing.

Be crafty- make better inserts than the saw makers- SAVE MONEY!

While you're tweaking your table saw, spend a few bucks and get a new machined pulley (instead of the factory cast one), a segmented drive belt and don't skimp on the blade. That is one place not to mess around. Spend the bucks on a Forrest Woodworker or Freud blade. So many guys I see have a great saw/fence setup but are cutting with a dull piece of crap. That's wasteful and dangerous.

Good luck with this project. It's worth the effort.

Brent in Durham