Personally I don't like to use beams because they cannot dodge, but the majority of fx of the missiles don't satisfy me. I would like to throw projectiles with appearance of beam but when I turn a beam into projectile with ffedit it doesn't go well. How do you solve this?
solve what? Projectiles and beams are set up in two completely different ways. As far as I know, you won't find a projectile that works like a beam without it looking incredibly awkward.