I'm quite sure the OP wonders why he bothered asking.
My advice, based on a few hundred hours of operating SEL of gravel/dirt, would be to ask the owner for his recommended procedures in that specific environment. Absent any detailed instructions the basic rules probably apply -
Use the minimum power required to get the airplane rolling
If the airplane doesn't move at a low to medium power setting then shut down and move it to a place where it will.
Never perform a full power static takeoff. Feed in the power as the aircraft accelerates.
Answers may be completely different if you are not paying for the prop and airframe damage.
Be aware though that not all airframe damage happens on takeoff. Tires may kick up gravel on landing roll out and it can hit the tail surfaces and, if really unlucky, the flaps, bottom of the wing and the prop(s).