Plato...It's not the shape of the stylus but its size that will degrade the 78's. The stylus tip diameter was considerably larger for 78's, and a LP stylus will scrape along the bottom of the groove instead of riding on the two sides.
Shure makes pickups and stylus to suit the 78 groove dimension, at very reasonable cost. Check their website. (Other manufacturers may also make such pickups).
Shure makes pickups and stylus to suit the 78 groove dimension, at very reasonable cost. Check their website. (Other manufacturers may also make such pickups).