Nails length affect picado posture, angle of attack and speed
https://youtu.be/NfSyCOFpf5M?t=14s
Tips on the shape of right hand finger nails
https://youtu.be/PGQkadtKIxI?t=2m09s
Ex.1/ 00:14 solo 1
Ex.4/ 02:13 topic
....
Proper thumb nail length
https://youtu.be/KmofPO9AERI?t=14s