I don't like your chances, every single set of Manfrotto sticks I've ever used have buckled (partially or fully) for one reason or another. We've had the Miller Jib on heavy duty Manfrotto sticks before and even with a lightly rigged scarlet on top, the legs still gave out.
I'd look for something more solid - Miller, Vinten, Ronford Baker or Sachtler are all reliable.