And, I'm finished! I didn't ruin anything, but I think I did sand through the finish a little bit after trying to smooth out the raised paint edges after two coats of polyurethane. It's ok, I'm still really happy.
Also, I discovered that lowering the leaves of the kitchen table allows this table top to fit right over the top and around the kitchen table, basically converting it into a dream chess table. I'm still going to take it to school and use it there, semi-permanently, but having the kitchen table option at home is pretty awesome.
Works great for Sinquefield Cup viewing, too!