Big pieces infused and small divines is a good setup. Some prefer all divines, depending on your mundus stone of choice. All robust agility jewelry is the way most have it set up, though some prefer healthy jewelry if they are struggling with gold and need to reach a higher health pool, which helps tons in pvp.

Impen is also really useful if you want maximum defense. Personally I focus more on dealing damage instead of protecting myself. My goal is to kill and not be seen, making impen useless for me. But yes, impen can be really useful. I've fought players with it and it gets quite annoying

To answer the actual question, you want divines on EVERYTHING for PVE. The meta used to be infused on big, divines on small, but with CP and the buffs to mundus stones, that is no longer the case. Divines is more DPS. For PVP, the answer is a little less clear. Nothing wrong with 7 divines, but a few pieces of impen is not the worst idea. I know people that run all 7 impen and it makes them really tanky.

Now to go on a gear rant, I personally prefer 3-4 piece Night mother over 3-4 piece ashen grip. You are basically trading DPS for survivabilty so that is your call. Another thing to consider is that for straight DPS, people are getting better numbers with 5 Nightmothers, 2 nerienth, 3 agility, Hundings/maelstrom Weapons. It only makes sense for one person in a group to go 5 night mothers however because everyone gets the benefit of the 5 piece bonus and it doesnt stack.

What I personally do: 5 Hundings (all armor Divines), 3 agility (robust), 1 piece bloodspawn for PvP or Kena for PvE, night mothers weapons and helm. If Maelstrom bow ever drops, that would be added for sure. I like really like the idea for PvP of Maelstrom 2H/bow, 3 agility, 5 hundings (perhaps willows path for crazy regen), 1 kena, 1 bloodspawn.