The distance from the saw blade to the front edge of the saw is very short. When pulling back the miter gauge, just the weight of the head will cause it to drop. The tabs are there to prevent this. It's difficult to know how accurately the slots are cut into the table top. Any sled runners will have to fit tightly so there is no side to side play or a sled won't work accurately. You also need to make sure you can adjust the blade so it's exactly parallel with the miter ways. Why not make some wood slides to match the miter gauge bar. Your first sleds may not be the greatest, consider them as an experiment. If it works, great, if not, you can look for other solutions. Once the tabs are cut, you can't put them back.