Awesome! Happy we got that sorted. As for stretching, try increasing the Constraint Iteration count and Simulation Iteration count in Project Settings->VICODynamics. If you don’t use too many soft-bodies then you should not see a performance hit. The stretchiness is a part of how the solver works, I believe I described it a few posts back, but essentially it’s the underlying algorithm which creates the softness.
Regarding the rest length function: I started putting it together and realized that non of the UObject types are marked as ‘BlueprintType’ which means that they can’t be stored in variables. D’oh! Is it an option for me to get you a C++ snippet which you can use as a static function in a BP Library class? If not, you’ll have to wait until I get the update out. Sorry about that and thank you for helping me discover this bug!