grade 5 is actually better, the grade 8 ay be stronger but the grade 5 wont sheer as easy, hence the reason you see grade 5 used in suspensions.
Dont get me started on drop brackets, especially the Tough Country, the entire bracket is suspect not jsut the eccentric adjuster cam and bolt.
TTB drop bracket kits dont hold up to heavy abuse, the taller the drop the worse it gets. Its not just your brackets I dont like its all of them.
Now with that said alot depends on how you drive, what the truck is used for (how much abuse you throw at it) and also what brand/type brackets you have.
There is no need for adjusting the pivot if you have the correct amount of coil (lift) compared to your drop bracket (axle pivots) and the correct camber shim (up to 2.75 correction on a 4x4)
You dont have to justify your new lift to me, I say run what ya brung and love to see any explorer get lifted, but I will give my opinions on these forums based on my experience and what I have seen over the years, which when it comes to the TTB, I like to think is quite a bit.