how to decide gear itemization

This may be on the verge of being put in the wrong forum, as it does pertain to a gear choice for myself, but I'm wondering how u decide which piece in a certain slot is better than the other. For instance, I currently have bolstered legplates from violet hold but I picked up legplates of inescapable death last night in nax 10. At first glance the nax pants look as they are better because they have natural points spent into avoidance as well as an extra socket but they lose like 20 or so defense rating. As I'm uncrittable regardless of item choice, this is of no issue to me. However, I read somewhere in this forum that before a certain point, defense gives more pure avoidance than block/dodge/parry rating. As of now I'm currently under the block cap, so how do I decide which piece has better itemization? I've picked the nax pants for the extra socket and 2 percent increased block rating but I just wanna know if the avoidance is acrtually in fact almost the same as what I would have had if I kept the 20 defense. I hope that post isn't too confusing