Winnie,
What prevents you from segregating helicopter and fixed wing operations to provide a safe distance that would eliminate the throwing of rocks?
As dust is a shallow and short radius issue at takeoff....why not do a Towering Takeoff as done for ages in the past with no hovering....do a quick very low hover to ascertain all is right with the aircraft....land back....then take off from the ground and climb out of the dust cloud on Instruments?
If there is no question of the aircraft being ready to fly.....skip the low hover and just do the ITO.