Fortunately my meta isn't super into Stone throwers. With this new list format I will either try and run 2x5 hexes and 3 Vargs or 2x3 Vargs and 5 hexes.
I've been running a fairly defensive Lord build that I got from
@Rizzo. Can't remember exact details off the top of my head but its worth pointing out that the Trickster's helm forces opponents to reroll ALL hits (or wounds, can't remember). This includes shooting, warmachines etc. With mundane shooters you can use your Hexes to screen your lord, as they'll provide soft cover. I'm not sure what the rules would be if they tried to shoot through two successive screens of Hexes in front of a Lord, whether the soft cover stacks. 2+ against shooting, 4++ and reroll hits/wounds.
@13ingo Hexes are fast cav, meaning only one needs to pass over the unit in movement. In reality they would swoop down into single file before fanning back out after hitting the unit. And don't forget they're completely ethereal meaning they can right RIGHT THROUGH terrain obstacles such as buildings and they don't take difficult terrain tests when riding through woods etc. Parking them behind scenery to prevent magic missile line of sight, then charging them through the scenery to attack (or doing your soul strider movement) can greatly improve longevity of the unit.