gnzart00 since no1 has answered, and if you haven't already. i would create 2 Ziva rigs (1 very simple, 1 less simple), select the zSolver, and in the channel box set solver to Iterative, and play with the value for the Solver Tolerance Factor. Try setting the integrator to BDF2 and see if it breaks or not. If you like any of the results with it, propagate it to your main rig, and see if it breaks, and if not, retune with it in mind