gridshell formfinding

Hi All,

I am writing my thesis on formfinding strategies for grid shell structures - I have attached a definition based on the particle-spring approach that's working but I can't get the constrain to curves (pull to curves) function to work -  I would like to constrain the edge anchor points to the curve on the original surface. Any help would be greatly appreciated.

Also does anyone have any thoughts on how to factor in the maximum bending radius of the material (cypress or oak for example) to the formfinding process so that a buildable form is produced ?