I never string ZX above 60lbs any longer. And I am still not convinced that prestretching (killing the resiliency and elasticity) of Zyex is really worth it. I think if your prestretch Ashaway Kevlar so that it won't stretch or settle into its braiding by hitting, the Zyex prestrung or not will work as a cross that provides some comfort and movement for the Ash Kev until the Kevlar breaks. I have not see the Zyex break when strung with Ashaway Kevlar mains before the Ash Kev breaks.