Which Shiro?

I would usually say that use the one that has a +IV on a stat that is the highest but in the case of Shiro his base speed is 30. A +spd Shiro is actually quite nice and prevents many doubles with a spd sacred seal and preferably Fury 3 in his a slot. The reason I think that +spd is better on Shiro is because a + def and def refined slaying lance Lukas outclasses Shiro as a defensive unit.