when i played classical guitar years back i ususally cut my fingernails but leave just a little bit sticking out so that I can get a bright tone if I want to with the little bit of nail, and a mellow tone easily with the fleshy part.
but now i play bass, i always cut until very short, no nails sticking out at all, and use the fleshy part always. I find that it gets the best tone, and if i want bright tone, i just player nearer the bridge. the nails sound somehow is pretty jarring, so just use fleshy part and play nesr the bridge is good enough for me.