To quote Sun Tze, Know thy enemy and Know thyself. Hitscan needs pinpoint accuracy and tracking… but once you master it you’d be a scary adversary. Projectiles you can get good at leading your shots etc… however suffers at longer rangers as players get better at juking/dodging during your projectile travel time.
It’s not going to be a 100% guarantee, but if you can force out even another 1% in your favour, you should try.
My advise against icepicks and arrows is to keen a decent amount of distance (say Illos Well, from one wall to another) and do long AD strafes in counter-sync to their fire rate. Sometimes vs hanzo… it is beneficial to do long strafes, and then just stand still (walking into the shaft of the arrow also counts as a hit).
a Key thing to note, DO NOT JUMP. it makes your movements predictable.
Hopefully this tip helps.