Softer strings need higher tensions in a poly hybrid. I string multi crosses 5 lbs. higher than the poly mains, sometimes only 4 lbs. higher if the main string is shaped. This will give you a much more consistent string bed with better performance overall. For a wider sweet spot, you can cheat down on the cross tension a bit, but this will compromise control.
But I would still use X-1 in the mains because of its coating.