@wormholes I think you’ll probably need to cut the 800 words down. My son’s was about 540 words and filled the space on the PDF completely. It was an essay he’d done earlier about a summer program he attended and what he learned about himself.
Make sure you check the verification PDF to make sure everything fits.
I’ve heard they aren’t too picky as far as essays for finalist qualification. There was a story passed down on CC about someone who wrote their essay about how the NM organization was elitist and deciding who gets NMSF based on one test is dumb. He didn’t move on to finalist, despite having good grades and a confirming score.