millipede problem

hello everyone

i'm trying to let millipede give me a (somewhat) accurate map of how gravity/other forces work on my mesh ,  so in which areas i need to for instance thicken the stucture or pierce it.   I've mapped the support plains/breps aswell as the forces by my knowledge properly, but no matter how I change materials of thickness, the results of the mesh remain relatively the same.  

i suspect i'm doing something wrong somewhere,  but I can't figure out what.  could you please help me with this?

i've added the rhino file aswell as the grasshopper file in the attachment

forward much obliged.